643

Possible Causes

• •Intermittent problem
• •Wire connected to terminal # 19 at the ECM is partially or completely shorted to power (Vbat, Vsw, Vrelay, etc.)
• •Poor ECM ground
• •Faulty ECM

Suggested Actions

1. 1Perform the On-Board (OBD) System Check
2. 2With Key ON, Engine Running, and System Mode set to 'Running', verify if DTC 643 displays
3. 3Using DST, check if 5Vext1 FB (VE5a_FB_raw) * 11/10 < 0.10 VDC
4. 4Inspect and repair wire connected to terminal # 19 at the ECM for a partial or complete short to power (Vbat, Vsw, Vrelay, etc.)
5. 5Inspect and repair poor ECM ground
6. 6Replace or repair faulty ECM

Related Power Solutions International, Inc. Fault Codes