Code p150a
Thread Starter
Teching In
Joined: May 2024
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Code p150a Good morning, I am posting here as a last resort, I just purchased an LS swapped 5.3 l 4L60 and NP 241C transfer case, 2004 Jeep Wrangler, the engine transmission transfer case TCM and PCM appear to have come from a donor 2008 Chevy Silverado manual transfer case vehicle, I am getting a check engine light with explanation p150A output speed sensor circuit,
I replaced the speed sensor, I owned the entire speed sensor circuit open closed and shorted, I've used my code reader in live data mode and live data graph mode, both show a consistent study speed signal,
After clearing the check engine light it will stay off during my entire first drive no matter how far the drive is, most recently I drove a 2-hour round trip no light, the light consistently returns on the second trip when I approach 30 miles an hour, after leaving the driveway, sometimes if I leave aggressively and quickly get up to speed I can avoid the light coming on for a few stops and starts, this issue is quite consistent as I have cleared the light about 30 times now All well checking and testing various items, there are no issues with shifting whatsoever.
However after clearing the light there is a very slight difference in shift firmness and timing.
I believe the builder did get into the tune because there is an AFM delete that has already been done according to the seller who is the second party,
Any suggestions or ideas would be greatly appreciated.
I replaced the speed sensor, I owned the entire speed sensor circuit open closed and shorted, I've used my code reader in live data mode and live data graph mode, both show a consistent study speed signal,
After clearing the check engine light it will stay off during my entire first drive no matter how far the drive is, most recently I drove a 2-hour round trip no light, the light consistently returns on the second trip when I approach 30 miles an hour, after leaving the driveway, sometimes if I leave aggressively and quickly get up to speed I can avoid the light coming on for a few stops and starts, this issue is quite consistent as I have cleared the light about 30 times now All well checking and testing various items, there are no issues with shifting whatsoever.
However after clearing the light there is a very slight difference in shift firmness and timing.
I believe the builder did get into the tune because there is an AFM delete that has already been done according to the seller who is the second party,
Any suggestions or ideas would be greatly appreciated.
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Joined: Aug 2010
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From: Ann Arbor, MI
Assuming the 4L60E is also from the 2008 donor vehicle (or at least a 2006+) then it will have an Input Speed Sensor (ISS). I wonder if the PCM is calculating what a "valid" speed sensor value should be based on the ISS and gear the transmission is in.
Lets see if anyone in this forum section has any ideas; if not I will move this thread to the Automatic Transmission section. The PCM/TCM has no way of knowing what gear the transmission is actually in; it only knows what gear it has commanded. Therefore I wonder if the transmission is shifting slowly and thereby causing the speed sensor to show a bad value and therefore setting the code. Aggressive driving will increase the line pressure in the transmission causing faster shifts.
Lets see if anyone in this forum section has any ideas; if not I will move this thread to the Automatic Transmission section. The PCM/TCM has no way of knowing what gear the transmission is actually in; it only knows what gear it has commanded. Therefore I wonder if the transmission is shifting slowly and thereby causing the speed sensor to show a bad value and therefore setting the code. Aggressive driving will increase the line pressure in the transmission causing faster shifts.
Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic approach.
- Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptor
DTC P150ATransmission Output Speed Signal CircuitDTC P150BTransmission Output Speed Sensor Circuit Intermittent
Circuit/System Description
The vehicle speed sensor (VSS), also called the output shaft speed sensor (OSS) creates an AC voltage as the rotor teeth pass through the magnetic field of the sensor. The transmission control module (TCM) converts the AC voltage into a vehicle speed signal, which is used to determine shift timing and torque converter clutch (TCC) scheduling. The TCM also provides a replicated transmission output speed signal (RTOSS) to the engine control module (ECM).Conditions for Running the DTC
P150A- The TCM indicates the transmission output speed signal is valid.
- Transmission output speed is 1,200 RPM or greater.
- Transmission output speed is greater than 300 RPM for 2 seconds.
- Transmission output speed has changed less then 500 RPM for 2 seconds.
Conditions for Setting the DTC
P150AThe replicated output speed is 60 RPM or less for 4.5 seconds.
P150B
The change in replicated output speed is 350 RPM or greater for 3.25 seconds.
Conditions for Clearing the DTC
P150A- P150A is a Type B DTC.
- The replicated output speed is 150 RPM or greater for at least 3 seconds.
- P150B is a Type B DTC.
- Transmission output speed is 150 RPM or greater for at least 2 seconds.
- The change in transmission output speed is 150 RPM or less for at least 3 seconds.
Diagnostic Aids
- A defective transmission output speed sensor (OSS) can cause inaccurate speed reading, creating faulty replicated output speed signal. Also, inspect the OSS for cracks, loose mounting, or damage.
- If the speed sensor passes testing, refer to Testing for Intermittent Conditions and Poor Connections.
Reference Information
Schematic ReferenceAutomatic Transmission Controls Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Transmission General Information
Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Transmission Control Module Scan Tool Information
Circuit/System Verification
If there are any other engine or transmission related DTCs set, diagnose those DTCs first. With a scan tool, observe the transmission output shaft speed sensor parameter for appropriate output RPM. Then in the engine controls data list, look for a functioning signal from the TCM.Circuit/System Testing
- Ignition OFF, disconnect the ECM connector (X3).
- Ignition ON, measure the voltage on the harness of the ECM connector (X3–66) for 5 V.
- If you have 5 V, test or replace the ECM.
- If the value is other than 5 V, test harness for:
- Short to Voltage
- Short to Ground
- Open
- If no trouble found, replace the TCM.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.Control Module References for ECM replacement, setup, and programming.
Thread Starter
Teching In
Joined: May 2024
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Hmmm, It does shift more firm at least first to second gear with a slightly aggressive throttle, and yes it is or does seem to be a 2008 engine transmission and transfer case all from the same donor vehicle I did this troubleshooting sheet all except for the test on the PCM I'll try it tomorrow, I did own the speed sensor harness for shorts to ground open and it all tests okay The only unusual thing I found is my new speed sensor ohms out to 1446 ohms and the old one ohmed out to 1256 ohms not sure if that matters though
Thread Starter
Teching In
Joined: May 2024
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So I completed the above test and I have no voltage at pin 66 with key on, I am going to go ahead and replace the TCM, before I do this can anybody tell me if it's possible that the person set this vehicle up change something in tuning that would cause this issue, I'm fairly certain that he would have had to have gotten into the tune to make this engine work with this Jeep, so please let me know if it's possible this could have been caused by PCM changes, otherwise I will take it to a tuner first, also can anybody recommend a tuner in the Stevens point area of Wisconsin?
Thread Starter
Teching In
Joined: May 2024
Posts: 7
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So I don't think this is the case but I'm going to replace the TCM, before I do so, can anyone confirm that this could not have been something done in tuning by an inexperienced tuner, or does it have to be a mechanical failure?
And if I replace the TCM with a flag one TCM, does it have to be tuned to work with The Jeep Wrangler, or is all tuning done in the ECM?
And if I replace the TCM with a flag one TCM, does it have to be tuned to work with The Jeep Wrangler, or is all tuning done in the ECM?
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