U18AA
Transmission Range Control Module Lost Communication With Engine Control Module
U18AA is an OBD-II diagnostic trouble code meaning: Transmission Range Control Module Lost Communication With Engine Control Module. Common causes: open or short circuit in the can bus, damage to the wiring harness between modules. Estimated repair cost: $56–278.
Symptoms
- Emergency operation of the gearbox
- The Check Engine light comes on
- Loss of engine power
- Gear shifting problems
- Unstable engine operation at idle
Causes
- Open or short circuit in the CAN bus
- Damage to the wiring harness between modules
- Transmission control module malfunction
- Problems with power supply or grounding of modules
- Software error in one of the modules
How to Fix
- Check the integrity of the CAN bus with a multimeter
- Inspect connectors and wiring harnesses for damage
- Check power supply and grounding of modules
- Read error codes from other modules
- If necessary, replace the faulty module
Related codes
FAQ
What does the U18AA code mean?
U18AA is an OBD-II diagnostic trouble code that indicates: Transmission Range Control Module Lost Communication With Engine Control Module
What causes a U18AA error code?
The most common causes of U18AA include: Open or short circuit in the CAN bus; Damage to the wiring harness between modules; Transmission control module malfunction; Problems with power supply or grounding of modules.
How do I fix a U18AA diagnostic trouble code?
To fix U18AA: Check the integrity of the CAN bus with a multimeter. Inspect connectors and wiring harnesses for damage. Check power supply and grounding of modules. For a complete diagnosis, use an OBD-II scanner.
Is it safe to drive with U18AA?
Limited driving only, diagnose soon
How much does it cost to fix U18AA?
The estimated repair cost for U18AA is $56–278. Actual cost depends on your vehicle, location, and labor rates.
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