What it means
Same as P23E1 with the control line shorted to ground. EGR mixes inert exhaust into intake to lower combustion peak temperature — too little raises NOx, too much causes misfires and rough running.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
EGR valve C controls exhaust-gas recirculation through the C stage or loop, where fitted. The module sets this code when the valve C control signal is low, consistent with a control line shorted to ground or a connection problem; it does not mean the signal is too high.
Common causes
Most likely first.
- Control line shorted to ground
- Connector pins corroded - high contact resistance
- Harness chafing through insulation
Symptoms
- Check engine light
- Possible rough idle, hesitation, or reduced power
- Increased emissions or failed emissions test
How to diagnose it
- Save freeze-frame data and check for related EGR C faults to establish when the low control condition occurs.
- Inspect the valve C connector and harness for corrosion, backed-out pins, or insulation chafed through against ground.
- Check for damaged or contaminated terminals that could interfere with the EGR valve C control signal.
- With the circuit isolated according to the manufacturer's procedure, test the valve C control wire for a short to ground.
- If the wiring passes, compare control-circuit readings and module output with the manufacturer's specification.
Common fixes
- Repair chafed valve C control wiring and secure it away from grounded surfaces.
- Clean or replace corroded or damaged EGR valve C connector terminals.
- Repair a confirmed short to ground in the valve C control circuit.
- Repair or replace the control module if it fails the specified circuit checks.
Can I keep driving?
If the engine runs normally, a short trip may be possible, but avoid heavy loads if it hesitates or loses power. The fault can disrupt EGR operation and increase emissions; rough running or misfires call for prompt diagnosis.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.