What it means
EGR B drive line stuck high — short to B+. 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 control B drives the valve in the engine’s second exhaust-gas-recirculation path, where fitted. P045D sets when the module detects an unusually high signal on the B control circuit, which can result from a short to battery voltage or a wiring or connection fault.
Common causes
Most likely first.
- Short to B+
- Connector pins corroded - high contact resistance
- Supply wire pinched against B+ source
Symptoms
- Check engine light on
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
How to diagnose it
- Check freeze-frame data and related EGR codes to confirm the high-signal fault is associated with control B.
- With the ignition off, inspect the EGR B harness for pinched or damaged insulation that could contact a power wire or other B+ source.
- Inspect the EGR B connector for corrosion, loose terminals, or signs of heat or moisture.
- Monitor the EGR B circuit reading while checking accessible harness sections for changes that point to an intermittent short.
- Use the wiring diagram to test the control wire for a short to battery voltage and compare the result with the manufacturer's specification.
- If the circuit is sound, check the EGR B actuator and module output following the manufacturer's diagnostic procedure.
Common fixes
- Repair wiring pinched against a battery-voltage source.
- Restore proper contact at loose or corroded EGR B connector terminals.
- Replace a failed EGR B solenoid or valve if testing confirms an internal electrical fault.
- Repair or replace the control module only after verifying its power, grounds, and B-circuit wiring.
Can I keep driving?
Drive gently only if the engine remains smooth; avoid heavy load if it knocks, hesitates, or loses power. Incorrect EGR control can raise NOx emissions and affect engine operation.
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.