Fix P0792: Mechanic’s solutions that WORKED

The P0792: Intermediate Shaft Speed Sensor ‘A’ Circuit Range/Performance code signals a problem in the Intermediate Shaft Speed Sensor ‘A’ Circuit, indicating performance issues or an out-of-range signal. This sensor plays a crucial role in monitoring the transmission’s shaft speed, which is vital for proper gear shifting and overall transmission performance. Faults in this sensor or its circuit can lead to transmission problems like erratic shifting or slipping gears.

P0792 quick overview

Meaning	P0792: Intermediate Shaft Speed Sensor ‘A’ Circuit Range/Performance
Is it serious?	The code is moderately serious and can affect the vehicle’s transmission behavior, possibly leading to further transmission damage if not addressed.
Possible causes	– Faulty Intermediate Shaft Speed Sensor – Damaged or corroded wiring and connectors – Transmission fluid issues (low level or poor quality) – Faulty Transmission Control Module (TCM)
How to diagnose?	Inspect Speed Sensor: Check the Intermediate Shaft Speed Sensor for any signs of damage or failure. Check Wiring and Connectors: Examine the sensor’s wiring and connectors for damage, corrosion, or looseness. Verify Fluid Level and Quality: Ensure the transmission fluid is at the correct level and in good condition. TCM Reset and Relearn: Perform a reset and relearn procedure on the Transmission Control Module after any repairs. Software Update: Look for any available software updates for the TCM and apply them if necessary.

How to fix P0792 – learn from mechanics

I looked into P0792 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Dodge

Vehicle Information: 2010 Dodge Grand Caravan SXT 3.8L – Limp Home When Hot, Intermittent Shudder in Reverse

Issue + Repair History:

• The vehicle experienced a limp home mode, stuck in 2nd gear with the MIL on.
• Codes P0734 and P0792 were pulled and cleared, but no issues occurred during initial test drive.
• On a subsequent day, four codes set and the vehicle exhibited problems during a test drive.
• Turbine speed and other speed sensor readings were normal.
• Noticed glitches in the APP2 signal without any APP codes.
• Initial shudder in reverse, which resolved after shifting back from drive.

Other OBD2 Codes + Test Results:

• P0734 – Incorrect gear ratio 4th
• P0792 – Compounder Speed
• P0733 – Incorrect gear ratio 3rd
• P1790 – Fault immediately after shift

Suggestions to Fix Issue:

• Replace the compounder assembly.
• Consider internal mechanical issues for gear ratio error codes.
• Check for metal debris on speed sensors as an indication of transmission wear.
• Measure the solenoid pack and conduct pressure tests on the transmission.
• Scope the a/c waveform and perform a test drive to diagnose potential mechanical problems.

Final Fix:

• A Dodge dealership 40 miles away honored the warranty.
• The problem was identified as the compounder, with shrapnel found in the valve body.
• Both the compounder and valve body were replaced under warranty.

Case #2: Chrysler

Vehicle Information: 2012 Chrysler Town & Country Touring L 3.6L – Limp Mode

Issue + Repair History:

• Came from a local body shop with a “no shift” issue.
• ECM/TCM was replaced with a new OEM unit and programmed by the dealer.
• Experienced gear ratio errors in multiple gears and a compounder speed ratio error.
• Quick learn and TCM re-flash were attempted without improvement.
• Vehicle would skip second gear, flare up the engine, then shift to and stick in third gear.
• Speed sensors read smoothly in scan data.
• The vehicle had been in a front-end collision, leading to PCM/TCM replacement.

Other OBD2 Codes + Test Results:

• P0731 – Gear ratio error 1st gear
• P0733 – Gear ratio error 3rd gear
• P0734 – Gear ratio error 4th gear
• P0736 – Gear ratio error reverse
• P0792 – Compounder speed ratio error
• P1790 – Fault immediately after shift

Suggestions to Fix Issue:

• Check all computer grounds and shift solenoids.
• Verify speed sensors receive 5v reference and return signal via TCM.
• Check fuses and shift solenoid function via scanner.
• Assess potential wiring issues due to the collision.
• Consider the possibility of a wiring problem, particularly for vehicles with significant collision damage.
• Use a scope for a more accurate picture of sensor activities.
• Ensure correct tire size and vehicle configuration in system settings.

Final Fix:

• Discovered that the output speed and transfer speed sensor wires were connected backwards due to an incorrect engine wire harness installation by the body shop.
• Correctly connecting the sensors and performing a quick learn resolved the issue.

Case #3: Ford

Vehicle Information: 2015 Ford F-150, 5.0L V8 – Transmission Slipping Issue

Issue + Repair History:

• The truck experienced a transmission slipping issue, particularly when shifting gears.
• Diagnostic codes revealed P0792 – Intermediate Shaft Speed Sensor ‘A’ Circuit Range/Performance.
• The truck had a recent transmission fluid change.
• No previous major transmission repairs.

Other OBD2 Codes + Test Results:

• P0792 – Intermediate Shaft Speed Sensor ‘A’ Circuit Range/Performance

Suggestions to Fix Issue:

• Inspect and possibly replace the Intermediate Shaft Speed Sensor.
• Check the wiring and connectors for damage or corrosion.
• Verify the transmission fluid level and quality.
• Reset and relearn the transmission control module after repairs.

Final Fix:

• The Intermediate Shaft Speed Sensor was replaced.
• The wiring harness connector to the sensor had minor corrosion and was cleaned.
• After the sensor replacement and wiring cleanup, the transmission performance returned to normal.

Case #4: Honda

Vehicle Information: 2013 Honda Accord, 2.4L I4 – Erratic Shifting

Issue + Repair History:

• The vehicle showed erratic shifting patterns, especially under load.
• Code P0792 was identified, indicating a problem with the transmission speed sensor.
• The vehicle had regular maintenance but no significant transmission work in the past.

Other OBD2 Codes + Test Results:

• P0792 – Intermediate Shaft Speed Sensor ‘A’ Circuit Range/Performance

Suggestions to Fix Issue:

• Replace the Intermediate Shaft Speed Sensor.
• Inspect the transmission control module for software updates.
• Check for any loose or damaged transmission wiring.

Final Fix:

• The Intermediate Shaft Speed Sensor was found to be faulty and was replaced.
• A software update for the transmission control module was also performed as part of the repair process.
• The issue was resolved, and the vehicle’s shifting returned to normal operation.

Case #5: Toyota

Vehicle Information: 2014 Toyota Camry, 2.5L – Delayed Gear Engagement

Issue + Repair History:

• The car experienced delayed engagement when shifting from park to drive.
• Code P0792 was logged, indicating an issue with the Intermediate Shaft Speed Sensor.
• The vehicle had a history of regular servicing, with no major transmission repairs.

Other OBD2 Codes + Test Results:

• P0792 – Intermediate Shaft Speed Sensor ‘A’ Circuit Range/Performance

Suggestions to Fix Issue:

• Examine and potentially replace the Intermediate Shaft Speed Sensor.
• Check the condition of the transmission fluid.
• Ensure all transmission electrical connections are secure and undamaged.

Final Fix:

• Replaced the Intermediate Shaft Speed Sensor due to failure.
• Found and repaired a minor leak in the transmission fluid line.
• After these repairs, the car’s gear engagement improved significantly.

Advice	Brief Description of Diagnostic Step
Replace Intermediate Shaft Speed Sensor	Inspect and, if necessary, replace the sensor to resolve signal issues.
Check Wiring and Connectors	Examine the sensor’s wiring and connectors for any damage, corrosion, or looseness.
Verify Transmission Fluid Level and Quality	Ensure the fluid is at the proper level and not contaminated or degraded.
Transmission Control Module (TCM) Reset and Relearn	Perform a reset and relearn procedure on the TCM after any repairs are made.
Software Update for TCM	Check for and apply any available software updates for the transmission control module.