What does this code mean?
The wording below belongs to the named make and communication. Match the complete code, reporting module, model year and engine before applying it.
A code identifies a detected condition, not a part that must automatically be replaced.
Manufacturer communications
1Original wording in English
CADILLAC, CHEVROLET, GMC
Reported code forms P18A1
This P/I advises to replace the valve body, not the TCM, for DTCs P1787, P27EC, P187E and/or P18A1 on vehicles equipped with an ETRS trans assembly.
Check vehicle applicability
8A listed vehicle is a research lead. Confirm the engine, production range and software in the manufacturer's information.
| Make | Model | Model year |
|---|---|---|
| Cadillac | ESCALADE | 2024 |
| Cadillac | ESCALADE ESV | 2024 |
| Chevrolet | SILVERADO 1500 | 2024 |
| Chevrolet | SUBURBAN | 2024 |
| Chevrolet | TAHOE | 2024 |
| GMC | SIERRA 1500 | 2024 |
| GMC | YUKON | 2024 |
| GMC | YUKON XL | 2024 |
Before replacing a part
Record codes and freeze-frame data. Check battery condition, related codes and visible wiring or hose damage. Follow the vehicle's diagnostic procedure and test results before replacing parts.
Can I keep driving?
A code alone cannot establish whether driving is safe. A flashing malfunction light, severe shaking, overheating, oil-pressure warning or loss of braking or steering needs prompt attention. Stop in a safe place and seek assistance when control or engine safety is affected. Follow the vehicle handbook.