P0403: EGR control circuit electrical fault
Exhaust gas recirculation circuit malfunction
Severity: Monitor
PartsAvatar rates P0403 as moderate and usually drivable; the computer may disable the EGR system.
It gets more serious if:
- Inspect soon: Have it inspected soon if the engine pings or pre-ignites on acceleration.
P0403 in short
P0403 means the computer found an open or short in the circuit that controls the EGR valve or its solenoid. Bad connections, water in the connector or a failed solenoid are the usual causes. The car is typically drivable, but the EGR system may be switched off and ping on acceleration.
The EGR system sends some exhaust back into the intake to cut nitrogen oxide emissions. The computer drives a solenoid or valve to control it.
P0403 means that electrical control circuit looks open or shorted. PartsAvatar lists the solenoid, its harness, loss of supply voltage, water intrusion and the computer.
When the circuit fails, the computer may disable EGR, and the engine can pre-ignite on acceleration.
Most likely causes
These are general causes for this code across vehicles. None is specific to one make or model.
Cause 1: Failed EGR solenoid or valve
Common general cause- Why it ranks here
- PartsAvatar lists a defective or blocked EGR solenoid.
- What would change this
- Rises if the solenoid fails a resistance or open check. Falls if it tests normal.
Cause 2: Damaged, corroded or wet wiring and connector
Common general cause- Why it ranks here
- PartsAvatar lists bad connections, water intrusion and chafed wiring; TaT lists open or short circuits.
- What would change this
- Rises if connectors show corrosion or wires are chafed. Falls if wiring tests continuous with supply voltage.
Cause 3: Engine computer fault
Possible — needs testing- Why it ranks here
- PartsAvatar lists the computer but only after wiring and solenoid.
- What would change this
- Rises if wiring and solenoid test good. Falls if either is faulty.
What to test first
Start at step 1. Each result tells you what it means and where to go next.
Step 1: Read the code and freeze-frame data, clear it and road test to see if it returns.
IfIt returns immediately
It meansInspect the wiring.
IfIt does not return
It meansMonitor it; the fault may be intermittent.
Step 2: Inspect the EGR solenoid wiring and connector for corrosion, water and damage, then have the solenoid tested for opens and shorts.
Warning:The EGR area gets very hot after running. Let the engine cool first.
IfCorrosion, damage or water is found
It meansRepair it and retest.
IfWiring is fine but the solenoid is open or shorted
It meansSolenoid failure.
IfBoth are fine
It meansComputer fault is possible.
Symptoms
- Check engine light
- Pinging or pre-ignition on acceleration Gets more serious: stop and have it checked.
How to fix
Step 1: With the engine off and cool, check that the EGR connector is fully seated and free of corrosion.
On your vehicle
ChevroletYour car
2017–2018 · Cruze
Supported by vehicle dataChevrolet bulletin PIE0489A names P0403 (also listed for equinox). GM engineering information about P0403; the summary only says it ends the need for field information. Also listed for the 2018 GMC Terrain. Whether it is still current is not verified.
PIE0489AStatus unverified
MIL on with P0403 set (Cruze, Equinox)
2017–2018cruze, equinox · issued · NHTSA 10154653
GM engineering information about P0403; the summary only says it ends the need for field information. Also listed for the 2018 GMC Terrain.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
RamYour car
2020–2022 · 1500
Supported by vehicle dataRam bulletin S2118000015 RevB names P0403. Bulletin for a check engine light with P0403, EGR control circuit open. Also listed for 2020-2022 Jeep Wrangler and Gladiator. The summary does not give the repair. Whether it is still current is not verified.
S2118000015 RevBStatus unverified
MIL on with P0403, EGR control circuit open (1500)
2020–20221500 · issued · NHTSA 10212342
Bulletin for a check engine light with P0403, EGR control circuit open. Also listed for 2020-2022 Jeep Wrangler and Gladiator. The summary does not give the repair.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
Related codes
P0403 questions
Can I drive with P0403?
PartsAvatar calls it moderate and typically drivable, but get it diagnosed rather than replacing parts blindly.
Sources and review
- P0403 OBD error code summary
- P0403 fault code entry
- Chevrolet PIE0489A: MIL on with P0403 set (Cruze, Equinox)
- Ram S2118000015 RevB: MIL on with P0403, EGR control circuit open (1500)
- Last reviewed
- Written by
- Saurabh K.
- Editorial review
- Pending
- Technician review
- Technician review pending
This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error