Fix P0902: Mechanic’s solutions that WORKED

The code P0902: Clutch Actuator Circuit Low points to a fault within the clutch actuator circuit, which is crucial for the vehicle’s gear engagement and shifting performance. It is often caused by issues ranging from a faulty clutch actuator to more complex electrical problems such as wiring issues or a bad transfer case module.

P0902 quick overview

Meaning	P0902: Clutch Actuator Circuit Low
Is it serious?	Yes, it can affect the vehicle’s ability to engage gears and drive normally.
Possible causes	– Faulty clutch actuator – Wiring or connector issues in the actuator circuit – Corrosion due to battery acid leakage – Faulty transfer case module – Ground connection problems
How to diagnose?	Check the clutch actuator: Inspect for any physical damage or signs of failure. Examine wiring and connectors: Look for damage, corrosion, or loose connections. Inspect the battery area: Ensure there is no acid leakage that could cause corrosion. Review ground connections: Check for proper grounding, especially under the battery tray. Test relays and fuses: Look for melted or burnt components that may interrupt the circuit. Program/reprogram module: If a new module is installed, ensure it is correctly programmed.

How to fix P0902 – learn from mechanics

I looked into P0902 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: Ford

Vehicle Information 2014 Ford Focus SE 2.0L Clutch A

Issue + Repair History

• MIL on with codes P0902 (Clutch A Actuator Circuit Low) and P0219 (Engine Over speed)
• Clutch assembly replaced, new Clutch A motor installed
• P0902 returned post-repair
• TCM replacement was indicated, sent to dealership

Other OBD2 Codes + Test Results

• P0902 – TCM
• P2872 – Unknown

What Are People Suggesting to Fix Issue

• Verify 5v reference and ground from TCM
• Test phase circuits and Hall Effect circuits with a scope
• If circuits test OK, consider TCM replacement
• Replace TCM as many have had this issue
• Swap actuators, clear codes, and perform TCM clutch relearn
• Replace transmission harness if issue persists

What Was the Final Fix

• After oscilloscope testing indicated U phase wire issue, used TCM installation resolved the problem

Case #2: Land Rover

Vehicle Information

• 2008 Land Rover LR3 SE 4.4L

Issue + Repair History

• Check Engine Light on, retrieved code P050B.
• Battery had corrosion, rinsed off negative terminal with water.
• Later, Low Range light flashed, no Reverse/Drive, and grinding noise in Park.
• Found codes P0902, P0915, and P0653.
• Corrosion found on Transfer Case Control Module (TCCM).

What Are People Suggesting to Fix Issue

• Check electrical components under the battery for water damage.
• Remove and clean TCCM to see if it fixes the issue.
• Might need a scan tool capable of programming modules.
• Calibrating the servo motor could be enough, no need for programming if the module is not new.
• A new module will require programming; a used one might only need calibrating.

What Was the Final Fix

• Replaced TCCM with a new one.
• Calibrated low and high range clutches with diagnostic tool.
• No additional programming was necessary with the new module.

Case #3: Ford

1. Vehicle Information 2013 Ford Focus SE, 2.0L engine

2. Issue + Repair History

• Check engine light on
• Vehicle dying out intermittently
• P0902 code (related to clutch actuator)
• Battery replaced due to poor condition

3. Other OBD2 Codes + Test Results

• No additional OBD2 codes mentioned

4. What are People Suggesting to Fix Issue

• Check Transmission Control Module (TCM) for issues, known to cause no starts
• Use a “Pulsar” and thermal imaging to find shorts
• Inspect for bad engine to frame ground or sensor grounds
• Try unplugging the MAF sensor to address crank no start condition
• Confirm if the P0902 code is correct
• Look for defects in connectors
• Use correct method for testing parasitic draw instead of a test light
• Consider Ford’s extended warranty program for TCM issues

5. What was the Final Fix

• The vehicle was sent to the dealer for a TCM replacement as part of a recall campaign.

Case #4: Land Rover

1. Vehicle Information 2005 Land Rover LR3 SE, 4.4L engine, Transfer Case

2. Issue + Repair History

• Noise heard, vehicle seemed to be in neutral during road test with customer.
• Multiple dashboard warning lights: low range light, amber brake light, traction control light, and ride level lights.
• The vehicle was able to move the next morning but was not road tested.
• Codes: P0902 clutch actuator circuit low, P0915 gearshift position sensor circuit range performance.
• Communication issues detected with several systems.
• Battery replaced, grounds checked, but problems persisted.

3. Other OBD2 Codes + Test Results

• IC no comm to ride level.
• Restraints no comm to dynamics IC.
• Ride level no data from dynamics.
• Dynamics no data from transfer case.

4. What are People Suggesting to Fix Issue

• Check the transfer case module for damage from battery acid.
• Inspect relays and fuse box under the hood for burns or melting.
• Review potential linkage failure to the contact switch on transfer case.
• Verify ground studs under the battery.
• If replacing the transfer case module, it needs to be programmed.
• Consider inspecting for melted or stuck relays/fuses.
• Check if the terrain response switch has liquid damage.

5. What was the Final Fix

• Transfer case module was damaged by battery acid and replaced.
• New module was programmed using an Integrated Diagnostic System (IDS).

Advice	Description of Diagnostic Step
Check Transfer Case Module	Inspect the transfer case module, particularly for damage from battery acid which can cause shorts.
Inspect Battery and Area	Examine the battery, its connections, and surrounding area for any signs of acid damage or leakage.
Review Ground Connections	Verify the integrity of ground studs, especially those under the battery tray, which are prone to corrosion.
Inspect Relays and Fuses	Look for any signs of melting or burning in the fuse box and relays under the hood, which could indicate electrical issues.
Program New Module	If a new transfer case module is installed, ensure it is properly programmed to calibrate with the vehicle’s systems.
Check Linkages	Examine the transfer case linkages for any signs of failure or misalignment that could affect the switch’s operation.
Consider Liquid Damage	Investigate the terrain response switch and other interior controls for damage due to spilled liquids.