P0651

Symptoms

• Check Engine light comes on
• Multiple sensor codes from circuit B at the same time
• Engine limp mode
• Unstable idle
• Dips and jerks when pressing the gas pedal

Causes

• Open circuit in reference voltage B
• Short circuit to ground
• Sensor with internal short circuit, “pulling” circuit B to ground
• Damage to the wiring harness (frayed, pinched)
• ECU malfunction (rare)

How to Fix

1. Read all codes - multiple sensor codes indicate a reference circuit problem
2. Check 5V voltage at circuit B sensor reference pins
3. Disconnect sensors one at a time to find a sensor with an internal short circuit
4. Inspect the wiring harness for damage
5. Check the ECU connector for oxidation and damage.
6. Replace the faulty sensor or repair the wiring

Related codes

Error P0651 by Vehicle Brand