P045C code meaning
EGR B Control Circuit Low
Powertrain system Generic code P04xx codes Check engine light
What P045C means
Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx. EGR B is a second EGR valve next to valve A – on diesels with two EGR circuits the low-pressure valve, which takes exhaust after the particulate filter and feeds it in before the turbo compressor. GM's diesels of 2016–18 and FCA's 2.2-litre diesel in the Jeep Wrangler use it. P045C means the drive circuit of valve B is shorted to ground (for valve A, P0489, GM uses 0.5 Ω or less with the driver off, MIL after two trips). The driver is switched off for protection and the valve stays in its rest position. GM lists this code among those that switch off the low-pressure EGR position control, but publishes no thresholds for it; the description follows the comparable valve A checks and CARB, which requires output circuits to be monitored.
P045C at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairAfter a drive cycle
Symptoms of P045C
- Check engine light on
- Low-pressure EGR switched off, possibly higher NOx
- Usually no change in driving
Common causes of P045C
- Most likelyControl wire chafed against ground (engine, exhaust)
- PossibleActuator motor winding shorted
- PossibleWater or corrosion in the connector
- Less likelyDriver in the engine module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
EGR valve bLow pressure EGR valveEGR wiringEngine control module
What each part of P045C means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 4 | Area: auxiliary emission controls (catalytic converter, EGR, EVAP). |
| 5C | The exact fault in that area. |
What to do next
- Note P045C and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P045C
What does P045C mean?
P045C means "EGR B Control Circuit Low". Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx. It is a generic code, so it means the same on every make.
Is it safe to drive with P045C?
Drive gently and only to a workshop. With P045C the car can go into limp mode (reduced power) to protect itself.
Will P045C fail an emissions test?
Yes, it can. P045C is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P045C to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P045C clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.