What does it mean?
P1402 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: EGR Vacuum Regulator Solenoid Valve -N18- Short circuit to B+ .
Symptoms
- MIL on
- Rough idle or a stumble because exhaust gas recirculation is no longer controlled
- Hesitation and poor throttle response
- Engine knock under load
- Idle may hang high or drop and stall when the valve stays open
- Emissions test failure with high nitrogen oxide readings
Likely causes
- Control wire shorted to battery positive along the harness
- Chafed insulation letting the control wire touch a power feed near the engine
- Internally shorted solenoid winding bridging supply and control
- Corroded or water filled solenoid connector bridging the terminals
- Damaged fuse box terminal or an incorrect relay feeding the circuit
- Control module output driver failed in the on state
- A previous repair splice or accessory wiring tapped into the circuit
How to fix it
- Unplug the solenoid and measure the control circuit with the ignition on: constant battery voltage confirms a short to power
- Measure the solenoid winding resistance and test for a short between the winding and its supply terminal
- Inspect the harness routing for chafe points against brackets, the manifold and power leads
- Check the connector for water, green corrosion and bridged terminals
- Command the solenoid with a scan tool and watch the vacuum or current change
- Repair the shorted wire or replace the solenoid as the tests indicate
- Before returning the vehicle, verify the vacuum lines and the EGR valve diaphragm hold vacuum