TCM MIL Request Circuit Malfunction

What this code means

The PCM has received a malfunction indicator lamp request from the Transmission Control Module. The TCM has detected a fault and is requesting the PCM to illuminate the Check Engine Light on behalf of the transmission system.

Symptoms

• Check Engine Light
• Transmission-related driveability issues
• Possible limp mode
• Harsh shifting

Common causes

• Transmission fault stored in TCM
• TCM communication issue
• Wiring fault in MIL request circuit
• TCM malfunction
• Transmission mechanical or electrical fault

Diagnostic steps

1. Scan TCM for stored DTCs (this code is a flag, not the actual fault)
2. Check TCM communication on scan tool
3. Inspect MIL request circuit wiring
4. Diagnose any transmission DTCs found in the TCM
5. Check transmission fluid level and condition

Repair notes

Diagnose and repair the transmission fault stored in the TCM; this code is an indicator that the real problem is in the TCM.

Other Powertrain codes on this vehicle