Code 38-18 High Diff Pressure Start Disable — Compressor start prevented due to high pressure differential

What does 38-18 mean?

The compressor is prevented from starting because the pressure differential is too high (above 100psi) and the PEV (Pressure Equalization Valve) was unsuccessful in lowering it. This protects the compressor. The fault clears once the pressure differential is below 100psi.

• Non-functioning PEV (e.g., mechanical failure).
• PEV coil not properly mounted to the valve.

Click steps to track your progress.

1. 1

   Verify that the PEV coil is securely attached to the PEV valve body.

2. 2

   If the coil is attached, replace the PEV harness and coil first (technician step).

3. 3

   If the problem is not fixed after replacing the harness and coil, replace the PEV body (technician step).