P23EF code meaning
Camshaft B Position Signal Output Circuit/Open (Bank 2)
What P23EF means
P23EF covers the last combination of this series: camshaft B, usually the exhaust shaft, on bank 2, the cylinder bank without cylinder 1. On V-engines with four camshafts the ECM can provide a separate phase output per shaft, and P23EF says the bank 2 exhaust output has lost circuit continuity – a broken wire, a terminal backed out of its connector or a missing load at the receiving end. No manufacturer documents P23EF publicly. GM evaluates its comparable camshaft A outputs only with the engine not cranking and the powertrain relay at 11 V or more, and those faults do not turn on the MIL. Shorts are separated out as P23F0 (to ground) and P23F1 (to power); bank 1 has the same open-circuit check under P23EC.
P23EF at a glance
- Check engine lightUsually not
- Emissions testNot an emissions code
- Limp modePossible
- Repair difficultyMedium
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P23EF
- Code stored without warning lamp on many vehicles
- Module relying on the signal sets its own fault codes
Common causes of P23EF
- Most likelyWire break in the bank 2 camshaft B output line
- PossibleTerminal backed out of the connector housing
- Less likelyReceiving module disconnected or with failed input
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Engine control moduleCam position signal b b2 outputWiring harness
What each part of P23EF means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| 3 | Area: ignition system or misfire. |
| EF | The exact fault in that area. |
What to do next
- Note P23EF 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 P23EF
What does P23EF mean?
P23EF means "Camshaft B Position Signal Output Circuit/Open (Bank 2)". P23EF covers the last combination of this series: camshaft B, usually the exhaust shaft, on bank 2, the cylinder bank without cylinder 1. It is a generic code, so it means the same on every make.
Is it safe to drive with P23EF?
Drive gently and only to a workshop. With P23EF the car can go into limp mode (reduced power) to protect itself.
Will P23EF fail an emissions test?
P23EF is not an emissions code, so on its own it usually does not fail an emissions test. Other stored codes or a lit check engine light still can.
How hard is P23EF to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. This is a job for a workshop.
Will P23EF clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.