U18CC
Transmission Range Control Module Lost Communication With ECM On Powertrain Expansion Bus
U18CC is an OBD-II diagnostic trouble code meaning: Transmission Range Control Module Lost Communication With ECM On Powertrain Expansion Bus. Common causes: open or short circuit in the can bus wiring, oxidation or damage to connectors. Estimated repair cost: $56–278.
Symptoms
- Emergency operation of the gearbox
- Inability to change gears
- The Check Engine light comes on
- Lack of response to selector switch
- Loss of engine power
Causes
- Open or short circuit in the CAN bus wiring
- Oxidation or damage to connectors
- Transmission control module (TRCM) malfunction
- Problems with the engine control module (ECM)
- Damage to CAN bus terminators
How to Fix
- Check the integrity of the CAN bus wiring between the ECM and TRCM
- Inspect and clean connector contacts
- Check power and ground at TRCM
- Read CAN bus parameters using an oscilloscope
- If necessary, replace faulty modules
Related codes
FAQ
What does the U18CC code mean?
U18CC is an OBD-II diagnostic trouble code that indicates: Transmission Range Control Module Lost Communication With ECM On Powertrain Expansion Bus
What causes a U18CC error code?
The most common causes of U18CC include: Open or short circuit in the CAN bus wiring; Oxidation or damage to connectors; Transmission control module (TRCM) malfunction; Problems with the engine control module (ECM).
How do I fix a U18CC diagnostic trouble code?
To fix U18CC: Check the integrity of the CAN bus wiring between the ECM and TRCM. Inspect and clean connector contacts. Check power and ground at TRCM. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with U18CC?
Do not drive — repair immediately
How much does it cost to fix U18CC?
The estimated repair cost for U18CC is $56–278. Actual cost depends on your vehicle, location, and labor rates.
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