ECM/PCM Power Relay De-Energized Too Early
The P068A code indicates that the ECM/PCM power relay de-energized before the engine control module completed its shutdown sequence. This can be caused by a faulty relay, wiring issues, low battery voltage, or a failing ECM. The relay should stay energized for a brief period after ignition off to allow the ECM to store data and perform post-cycle checks.
1. Most Common Causes
- Faulty ECM/PCM power relay with worn contacts
- Deteriorated ECM/PCM voltage hold-up capacitor with reduced capacity
- Excessive resistance or intermittent connection in the relay control circuit wiring
- Internal ECM/PCM failure in the relay monitoring circuit
- Weak battery or corroded battery terminals causing premature voltage drop
- Increased resistance or poor contact in the relay power supply fuse
- Ignition circuit interference or intermittent disconnection during shutdown
2. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine may stall or have difficulty starting
- Loss of memory settings (radio, clock, etc.)
- Intermittent electrical issues
3. Step-by-Step Diagnosis
Step 1: Scan for additional codes and document freeze frame data.
Step 2: Inspect the ECM/PCM power relay and its connections for corrosion or damage.
Step 3: Test battery voltage and charging system; ensure battery is fully charged.
Step 4: Check relay control circuit for shorts or opens using a multimeter.
Step 5: If all else is normal, suspect a failing ECM/PCM and perform further testing.
4. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended to drive long distances as the issue may cause stalling or no-start conditions. Have it diagnosed promptly.
How much does it cost to fix?▼
Typically $50-$150 for relay replacement and basic diagnostics. ECM replacement can cost $500-$1000+.
5. Commonly Affected Makes
This is a generic OBD2 code, potentially applicable to any manufacturer using this diagnostic standard.