Sound like VSS (Vehicle Speed Sensor) that will usually set a trouble code in the computer. Is the check engine lite on or has it been on? Even if it hasn't id start by having the computer scanned for trouble codes and go from there.
Also, its rare but not impossible, having a problem with the Ignition Switch. The power for the Transmission Shift solenoids gets its power from the ignition switch. The ignition switch has more than one circuit running through it to power different systems in the vehicle when the ignition is on. No power to the transmission solenoids and the transmission defaults to 2nd or 3rd gear. This dont mean that your ignition swtich is necesarily bad, some wires are bad in the steering column portion wires, not in the key cylinder. Test it.
DTC P0157 - 02 Sensor Circuit Low Voltage (Bank 2 Sensor 2) This code refers to a fault in the post-catalyst o2 sensor on Bank 2. First, a basic run-down of the catalyst: The Catalytic Converter is used to help control tailpipe emissions, to "clean up" the exhaust, if you will. The PCM (Powertrain Control Module) uses the signal from the heated oxygen sensor to the rear of the catalyst to monitor the catalyst's efficiency by comparing it to the o2 sensors in front of the catalyst.
If the PCM sees little or no difference between the exhaust quality in post- and pre- catalyst sensors then it knows that the catalyst is not working properly. To over simplify: a post-cat sensor's main job is to monitor catalyst efficiency, not control fuel management (although they can have a measure of influence over the front o2 sensor's operation, we'll just stick to basics for the sake of simplicity).
If you have a P0157, that doesn't mean your catalyst is bad (in fact, it usually never does). This code basically means that the Bank 2, Sensor 2 (or second o2 sensor back on bank 2) signal voltage is below what is considered normal for that sensor. It's a four wire sensor being supplied a 0.5 volt reference voltage (usually on the signal wire) and a ground, as well as a power and ground circuit for the o2 sensor heater element. Changes in oxygen content cause resistance changes in the sensor's signal circuit. This changing resistance affects the 0.5 volts on the signal/reference circuit. A heated o2 sensor is capable of switching between 0.1 volts and 0.9 volts. However, a properly working post-catalyst sensor will exhibit small changes at a slower rate than front (pre-catalyst) o2 sensors. It may switch slightly above and below 0.45 volts at the rate of about 1 switch per second or less(depends on the vehicle). The PCM monitors this changing signal to determine if the catalyst is working properly. If the PCM determines that the post-cat o2 sensor signal voltage is below a certain threshold for too long, P0157 will set.
Symptoms: Usually rear o2 sensor problems won't cause drivability issues since they are an input that measures catalyst efficiency (unlike front o2 sensors). However if you have other codes present, like lean codes or pre-o2 sensor codes, then they may cause drivability problems as well as P0143.
The following symptoms may be present: * MIL (Malfunction Indicator Lamp) illumination * Engine performance issues * Engine running rough * Engine running rich (only if PCM is trying to add fuel to compensate for low o2 sensor voltage reading) * Engine running lean (only if vacuum leak is large enough that PCM can't compensate by adding fuel) * Poor idle
Causes: If you have reason to believe that your engine is running lean, fix that problem first, then clear codes and see if the P0157 code resets. An engine that is running lean could set this code, but usually there will be lean codes (P0171, P0174) present. The following could be causes: * Air leaks in exhaust in front of o2 sensor giving false reading * Engine running excessively lean * O2 sensor connector damaged/corroded * O2 sensor signal circuit is shorted to ground * O2 sensor ground circuit is open * O2 sensor has failed (it may be contaminated with fuel or coolant) * PCM has failed
Possible Solutions: It's always good to start with checking for air leaks in the exhaust manifold and in the exhaust pipes. Fix these first.
With KOER (Key on engine running) use a scan tool or a voltmeter check the o2 sensor signal voltage with engine warm. You may have to increase the RPM to a fast idle to check the voltage of the bank 2,2 sensor. If it's voltage is stuck low (less than 0.5 volts may not be enough to set the code, but it depends on the vehicle) and you don't have any other o2 sensor codes present in the PCM, then it's a good bet that the sensor is bad. If the voltage isn't stuck low and the o2 sensor seems to be operating fine, it's likely sticking low intermittently. This often turns out to be the sensor. In either case, replacing the sensor can be an effective way to diagnose the problem. But it can also be an expensive diagnostic tool, especially if it turns out to be a wiring issue, instead of a sensor.
So, if you're interested in knowing for sure what the problem is before spending unnecessarily, then perform the following: 1. Turn off the engine and unplug the 2,2 o2 sensor connector. Inspect for corrosion, etc. Repair as necessary. Make sure that there is battery voltage present and ground present for the o2 sensor heater. If there isn't, then diagnose that first then retest. The o2 sensor depends on the heater to warm it up so it can start working quicker. If the heater element is bad or there isn't the proper voltage supplying it, the sensor may set this code. Usually heater problems have codes associated with them, too. If you find there is no battery voltage feeding the o2 sensor use the associated code to diagnose that. If you find the heater element bad, replace the sensor.
If the heater element checks out then, using a jumper wire, supply a chassis ground to the o2 sensor connector(PCM side) ground circuit. Now observe the scan tool bank 2,2 o2 sensor reading. If it is now at about a half a volt then replace the o2 sensor. If, after supplying a ground to the unplugged PCM side of the o2 sensor connector, the voltage reading doesn't change then check the harness for short to ground. Check for harness making contact with exhaust components. Check pins for damage, and for moisture. Repair as necessary. If you can find no harness problems, then the PCM may be at fault.
DTC P0161 - Oxygen O2 Sensor Circuit Low Voltage (Bank 2, Sensor 2) It basically means the PCM detected either an excessive current draw, or an open or short in the circuit powering the oxygen sensor's heater circuit. This is in reference to the Heated Oxygen Sensor (2) located rear of catalytic converter (Bank 2).
Symptoms: There will likely be no obvious symptoms other than MIL illumination.
Causes: A code P0161 may mean that one or more of the following has happened: * HO2S heater power circuit open * HO2S heater ground circuit open * HO2S signal tracking (due to oil or moisture in the connector) * HO2S is damaged or has failed PCM has failed
Possible Solutions: * Replace HO2 Sensor * Repair open or short in power circuit * Repair open or short in ground circuit * Repair damaged connector due to tracking
DTC P0785 - 3-2 Shift Solenoid Circuit Electrical The P0785 code is detected when the PCM detects a continuous open, short to ground or short to power in the 3-2 SS valve assembly circuit.
The 3-2 Shift Solenoid valve assembly is a normally-closed, and the controls the 3-2 downshift. The Powertrain Control Module (PCM) controls the solenoid by providing a ground path. During a 3-2 downshift, the 2-4 band applies as the 3-4 clutch releases. The PCM varies the timing between the 3-4 clutch release and the 2-4 band apply depending on the vehicle speed and the throttle position.
Symptoms: - Engine Light ON (or Service Engine Soon Warning Light) - Transmission may not shift to the next gear.
Possible causes: - Low transmission fluid level - Dirty transmission fluid - Faulty shifting solenoid valve - Shifting solenoid valve harness or connectors - Shifting solenoid valve circuit is open or shorted
Hope help with this.DTC P0157 - 02 Sensor Circuit Low Voltage (Bank 2 Sensor 2) This code refers to a fault in the post-catalyst o2 sensor on Bank 2. First, a basic run-down of the catalyst: The Catalytic Converter is used to help control tailpipe emissions, to "clean up" the exhaust, if you will. The PCM (Powertrain Control Module) uses the signal from the heated oxygen sensor to the rear of the catalyst to monitor the catalyst's efficiency by comparing it to the o2 sensors in front of the catalyst.
If the PCM sees little or no difference between the exhaust quality in post- and pre- catalyst sensors then it knows that the catalyst is not working properly. To over simplify: a post-cat sensor's main job is to monitor catalyst efficiency, not control fuel management (although they can have a measure of influence over the front o2 sensor's operation, we'll just stick to basics for the sake of simplicity).
If you have a P0157, that doesn't mean your catalyst is bad (in fact, it usually never does). This code basically means that the Bank 2, Sensor 2 (or second o2 sensor back on bank 2) signal voltage is below what is considered normal for that sensor. It's a four wire sensor being supplied a 0.5 volt reference voltage (usually on the signal wire) and a ground, as well as a power and ground circuit for the o2 sensor heater element. Changes in oxygen content cause resistance changes in the sensor's signal circuit. This changing resistance affects the 0.5 volts on the signal/reference circuit. A heated o2 sensor is capable of switching between 0.1 volts and 0.9 volts. However, a properly working post-catalyst sensor will exhibit small changes at a slower rate than front (pre-catalyst) o2 sensors. It may switch slightly above and below 0.45 volts at the rate of about 1 switch per second or less(depends on the vehicle). The PCM monitors this changing signal to determine if the catalyst is working properly. If the PCM determines that the post-cat o2 sensor signal voltage is below a certain threshold for too long, P0157 will set.
Symptoms: Usually rear o2 sensor problems won't cause drivability issues since they are an input that measures catalyst efficiency (unlike front o2 sensors). However if you have other codes present, like lean codes or pre-o2 sensor codes, then they may cause drivability problems as well as P0143.
The following symptoms may be present: * MIL (Malfunction Indicator Lamp) illumination * Engine performance issues * Engine running rough * Engine running rich (only if PCM is trying to add fuel to compensate for low o2 sensor voltage reading) * Engine running lean (only if vacuum leak is large enough that PCM can't compensate by adding fuel) * Poor idle
Causes: If you have reason to believe that your engine is running lean, fix that problem first, then clear codes and see if the P0157 code resets. An engine that is running lean could set this code, but usually there will be lean codes (P0171, P0174) present. The following could be causes: * Air leaks in exhaust in front of o2 sensor giving false reading * Engine running excessively lean * O2 sensor connector damaged/corroded * O2 sensor signal circuit is shorted to ground * O2 sensor ground circuit is open * O2 sensor has failed (it may be contaminated with fuel or coolant) * PCM has failed
Possible Solutions: It's always good to start with checking for air leaks in the exhaust manifold and in the exhaust pipes. Fix these first.
With KOER (Key on engine running) use a scan tool or a voltmeter check the o2 sensor signal voltage with engine warm. You may have to increase the RPM to a fast idle to check the voltage of the bank 2,2 sensor. If it's voltage is stuck low (less than 0.5 volts may not be enough to set the code, but it depends on the vehicle) and you don't have any other o2 sensor codes present in the PCM, then it's a good bet that the sensor is bad. If the voltage isn't stuck low and the o2 sensor seems to be operating fine, it's likely sticking low intermittently. This often turns out to be the sensor. In either case, replacing the sensor can be an effective way to diagnose the problem. But it can also be an expensive diagnostic tool, especially if it turns out to be a wiring issue, instead of a sensor.
So, if you're interested in knowing for sure what the problem is before spending unnecessarily, then perform the following: 1. Turn off the engine and unplug the 2,2 o2 sensor connector. Inspect for corrosion, etc. Repair as necessary. Make sure that there is battery voltage present and ground present for the o2 sensor heater. If there isn't, then diagnose that first then retest. The o2 sensor depends on the heater to warm it up so it can start working quicker. If the heater element is bad or there isn't the proper voltage supplying it, the sensor may set this code. Usually heater problems have codes associated with them, too. If you find there is no battery voltage feeding the o2 sensor use the associated code to diagnose that. If you find the heater element bad, replace the sensor.
If the heater element checks out then, using a jumper wire, supply a chassis ground to the o2 sensor connector(PCM side) ground circuit. Now observe the scan tool bank 2,2 o2 sensor reading. If it is now at about a half a volt then replace the o2 sensor. If, after supplying a ground to the unplugged PCM side of the o2 sensor connector, the voltage reading doesn't change then check the harness for short to ground. Check for harness making contact with exhaust components. Check pins for damage, and for moisture. Repair as necessary. If you can find no harness problems, then the PCM may be at fault.
DTC P0161 - Oxygen O2 Sensor Circuit Low Voltage (Bank 2, Sensor 2) It basically means the PCM detected either an excessive current draw, or an open or short in the circuit powering the oxygen sensor's heater circuit. This is in reference to the Heated Oxygen Sensor (2) located rear of catalytic converter (Bank 2).
Symptoms: There will likely be no obvious symptoms other than MIL illumination.
Causes: A code P0161 may mean that one or more of the following has happened: * HO2S heater power circuit open * HO2S heater ground circuit open * HO2S signal tracking (due to oil or moisture in the connector) * HO2S is damaged or has failed PCM has failed
Possible Solutions: * Replace HO2 Sensor * Repair open or short in power circuit * Repair open or short in ground circuit * Repair damaged connector due to tracking
DTC P0785 - 3-2 Shift Solenoid Circuit Electrical The P0785 code is detected when the PCM detects a continuous open, short to ground or short to power in the 3-2 SS valve assembly circuit.
The 3-2 Shift Solenoid valve assembly is a normally-closed, and the controls the 3-2 downshift. The Powertrain Control Module (PCM) controls the solenoid by providing a ground path. During a 3-2 downshift, the 2-4 band applies as the 3-4 clutch releases. The PCM varies the timing between the 3-4 clutch release and the 2-4 band apply depending on the vehicle speed and the throttle position.
Symptoms: - Engine Light ON (or Service Engine Soon Warning Light) - Transmission may not shift to the next gear.
Possible causes: - Low transmission fluid level - Dirty transmission fluid - Faulty shifting solenoid valve - Shifting solenoid valve harness or connectors - Shifting solenoid valve circuit is open or shorted
Have you ever had the pan off and change the filter? The filter may be clogged up and restricting fluid flow. Have you had the fluid replaced and serviced as described in the manual? How many miles are on your truck?
It is very possible you could have a selenoid issue. 250,000 miles is a lot of miles on one of these transmissions. Not changing the fluid or cleaning the filter can lead to a gunky build up and make the selenoid and gears work much harder than they need to, a good flush and cleanout would be a place to start, you could possibly clean it up enought so the gears shift much easier and thus taking a load off the selenoid. The bearings and bushings on the selenoids get worn and stubborn after a lot of hard use. Transmissions are much more complictated than they used to be, not as much for the typicall person to fix on their own. Nowdays they have a lot of different sensors and selenoids that need a computer to anylize. With as many miles you got out of this tranny, you can't complain if it needs a little service. Was the last part of your question asking about hardness, like in grease and oil harndening or were you wondering about the wire harness?It is very possible you could have a selenoid issue. 250,000 miles is a lot of miles on one of these transmissions. Not changing the fluid or cleaning the filter can lead to a gunky build up and make the selenoid and gears work much harder than they need to, a good flush and cleanout would be a place to start, you could possibly clean it up enought so the gears shift much easier and thus taking a load off the selenoid. The bearings and bushings on the selenoids get worn and stubborn after a lot of hard use. Transmissions are much more complictated than they used to be, not as much for the typicall person to fix on their own. Nowdays they have a lot of different sensors and selenoids that need a computer to anylize. With as many miles you got out of this tranny, you can't complain if it needs a little service. Was the last part of your question asking about hardness, like in grease and oil harndening or were you wondering about the wire harness?
Answers & Comments
Sound like VSS (Vehicle Speed Sensor) that will usually set a trouble code in the computer. Is the check engine lite on or has it been on? Even if it hasn't id start by having the computer scanned for trouble codes and go from there.
Also, its rare but not impossible, having a problem with the Ignition Switch. The power for the Transmission Shift solenoids gets its power from the ignition switch. The ignition switch has more than one circuit running through it to power different systems in the vehicle when the ignition is on. No power to the transmission solenoids and the transmission defaults to 2nd or 3rd gear. This dont mean that your ignition swtich is necesarily bad, some wires are bad in the steering column portion wires, not in the key cylinder. Test it.
Keep us updated.
DTC P0157 - 02 Sensor Circuit Low Voltage (Bank 2 Sensor 2)
This code refers to a fault in the post-catalyst o2 sensor on Bank 2. First, a basic run-down of the catalyst: The Catalytic Converter is used to help control tailpipe emissions, to "clean up" the exhaust, if you will. The PCM (Powertrain Control Module) uses the signal from the heated oxygen sensor to the rear of the catalyst to monitor the catalyst's efficiency by comparing it to the o2 sensors in front of the catalyst.
If the PCM sees little or no difference between the exhaust quality in post- and pre- catalyst sensors then it knows that the catalyst is not working properly. To over simplify: a post-cat sensor's main job is to monitor catalyst efficiency, not control fuel management (although they can have a measure of influence over the front o2 sensor's operation, we'll just stick to basics for the sake of simplicity).
If you have a P0157, that doesn't mean your catalyst is bad (in fact, it usually never does). This code basically means that the Bank 2, Sensor 2 (or second o2 sensor back on bank 2) signal voltage is below what is considered normal for that sensor. It's a four wire sensor being supplied a 0.5 volt reference voltage (usually on the signal wire) and a ground, as well as a power and ground circuit for the o2 sensor heater element. Changes in oxygen content cause resistance changes in the sensor's signal circuit. This changing resistance affects the 0.5 volts on the signal/reference circuit. A heated o2 sensor is capable of switching between 0.1 volts and 0.9 volts. However, a properly working post-catalyst sensor will exhibit small changes at a slower rate than front (pre-catalyst) o2 sensors. It may switch slightly above and below 0.45 volts at the rate of about 1 switch per second or less(depends on the vehicle). The PCM monitors this changing signal to determine if the catalyst is working properly. If the PCM determines that the post-cat o2 sensor signal voltage is below a certain threshold for too long, P0157 will set.
Symptoms: Usually rear o2 sensor problems won't cause drivability issues since they are an input that measures catalyst efficiency (unlike front o2 sensors). However if you have other codes present, like lean codes or pre-o2 sensor codes, then they may cause drivability problems as well as P0143.
The following symptoms may be present:
* MIL (Malfunction Indicator Lamp) illumination
* Engine performance issues
* Engine running rough
* Engine running rich (only if PCM is trying to add fuel to compensate for low o2 sensor voltage reading)
* Engine running lean (only if vacuum leak is large enough that PCM can't compensate by adding fuel)
* Poor idle
Causes: If you have reason to believe that your engine is running lean, fix that problem first, then clear codes and see if the P0157 code resets. An engine that is running lean could set this code, but usually there will be lean codes (P0171, P0174) present. The following could be causes:
* Air leaks in exhaust in front of o2 sensor giving false reading
* Engine running excessively lean
* O2 sensor connector damaged/corroded
* O2 sensor signal circuit is shorted to ground
* O2 sensor ground circuit is open
* O2 sensor has failed (it may be contaminated with fuel or coolant)
* PCM has failed
Possible Solutions: It's always good to start with checking for air leaks in the exhaust manifold and in the exhaust pipes. Fix these first.
With KOER (Key on engine running) use a scan tool or a voltmeter check the o2 sensor signal voltage with engine warm. You may have to increase the RPM to a fast idle to check the voltage of the bank 2,2 sensor. If it's voltage is stuck low (less than 0.5 volts may not be enough to set the code, but it depends on the vehicle) and you don't have any other o2 sensor codes present in the PCM, then it's a good bet that the sensor is bad. If the voltage isn't stuck low and the o2 sensor seems to be operating fine, it's likely sticking low intermittently. This often turns out to be the sensor. In either case, replacing the sensor can be an effective way to diagnose the problem. But it can also be an expensive diagnostic tool, especially if it turns out to be a wiring issue, instead of a sensor.
So, if you're interested in knowing for sure what the problem is before spending unnecessarily, then perform the following: 1. Turn off the engine and unplug the 2,2 o2 sensor connector. Inspect for corrosion, etc. Repair as necessary. Make sure that there is battery voltage present and ground present for the o2 sensor heater. If there isn't, then diagnose that first then retest. The o2 sensor depends on the heater to warm it up so it can start working quicker. If the heater element is bad or there isn't the proper voltage supplying it, the sensor may set this code. Usually heater problems have codes associated with them, too. If you find there is no battery voltage feeding the o2 sensor use the associated code to diagnose that. If you find the heater element bad, replace the sensor.
If the heater element checks out then, using a jumper wire, supply a chassis ground to the o2 sensor connector(PCM side) ground circuit. Now observe the scan tool bank 2,2 o2 sensor reading. If it is now at about a half a volt then replace the o2 sensor. If, after supplying a ground to the unplugged PCM side of the o2 sensor connector, the voltage reading doesn't change then check the harness for short to ground. Check for harness making contact with exhaust components. Check pins for damage, and for moisture. Repair as necessary. If you can find no harness problems, then the PCM may be at fault.
DTC P0161 - Oxygen O2 Sensor Circuit Low Voltage (Bank 2, Sensor 2)
It basically means the PCM detected either an excessive current draw, or an open or short in the circuit powering the oxygen sensor's heater circuit. This is in reference to the Heated Oxygen Sensor (2) located rear of catalytic converter (Bank 2).
Symptoms: There will likely be no obvious symptoms other than MIL illumination.
Causes: A code P0161 may mean that one or more of the following has happened:
* HO2S heater power circuit open
* HO2S heater ground circuit open
* HO2S signal tracking (due to oil or moisture in the connector)
* HO2S is damaged or has failed PCM has failed
Possible Solutions:
* Replace HO2 Sensor
* Repair open or short in power circuit
* Repair open or short in ground circuit
* Repair damaged connector due to tracking
DTC P0785 - 3-2 Shift Solenoid Circuit Electrical
The P0785 code is detected when the PCM detects a continuous open, short
to ground or short to power in the 3-2 SS valve assembly circuit.
The 3-2 Shift Solenoid valve assembly is a normally-closed, and the
controls the 3-2 downshift. The Powertrain Control Module (PCM) controls
the solenoid by providing a ground path. During a 3-2 downshift, the
2-4 band applies as the 3-4 clutch releases. The PCM varies the timing
between the 3-4 clutch release and the 2-4 band apply depending on the
vehicle speed and the throttle position.
Symptoms:
- Engine Light ON (or Service Engine Soon Warning Light)
- Transmission may not shift to the next gear.
Possible causes:
- Low transmission fluid level
- Dirty transmission fluid
- Faulty shifting solenoid valve
- Shifting solenoid valve harness or connectors
- Shifting solenoid valve circuit is open or shorted
Hope help with this.
Have you ever had the pan off and change the filter? The filter may be clogged up and restricting fluid flow. Have you had the fluid replaced and serviced as described in the manual? How many miles are on your truck?
It is very possible you could have a selenoid issue. 250,000 miles is a lot of miles on one of these transmissions. Not changing the fluid or cleaning the filter can lead to a gunky build up and make the selenoid and gears work much harder than they need to, a good flush and cleanout would be a place to start, you could possibly clean it up enought so the gears shift much easier and thus taking a load off the selenoid. The bearings and bushings on the selenoids get worn and stubborn after a lot of hard use. Transmissions are much more complictated than they used to be, not as much for the typicall person to fix on their own. Nowdays they have a lot of different sensors and selenoids that need a computer to anylize. With as many miles you got out of this tranny, you can't complain if it needs a little service.
Was the last part of your question asking about hardness, like in grease and oil harndening or were you wondering about the wire harness?