P2B49 code meaning
B Camshaft Position Actuator Position Sensor B Circuit Low Bank 1
Powertrain system Generic code P2Bxx codes Check engine light
What P2B49 means
With P2B49 the module reads too low a signal from position sensor B at the exhaust camshaft actuator of bank 1. A short between signal line and ground, a sensor with an internal short or a missing feed are the usual suspects. The nearest public manufacturer reference is P34BE on the Mercedes M176/M177: the sensor of exhaust solenoid 1 for CAMTRONIC, bank 1, described as shorted to ground. For P2B49 itself no manufacturer document is available. GM sets the comparable exhaust code of its L3B (P2C14) when the driver is on and the circuit shows at most 0.5 Ω to ground. Chafe points on the harness running along the cylinder head cover are worth checking first. Exhaust bank 1 high fault: P2B4A.
P2B49 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P2B49
- Check engine light on
- Exhaust cam lift change switched off
- Occasionally further sensor codes
Common causes of P2B49
- Most likelySignal line shorted to ground
- PossibleSensor shorted internally
- Less likelySensor feed missing
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
B camshaft position actuator pos sensor b b1Wiring harnessECM
What each part of P2B49 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 2 | Generic code (second SAE range): it means the same on every make. |
| B | Area: hybrid propulsion. |
| 49 | The exact fault in that area. |
What to do next
- Note P2B49 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 P2B49
What does P2B49 mean?
P2B49 means "B Camshaft Position Actuator Position Sensor B Circuit Low Bank 1". With P2B49 the module reads too low a signal from position sensor B at the exhaust camshaft actuator of bank 1. It is a generic code, so it means the same on every make.
Is it safe to drive with P2B49?
Drive gently and only to a workshop. With P2B49 the car can go into limp mode (reduced power) to protect itself.
Will P2B49 fail an emissions test?
Yes, it can. P2B49 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 P2B49 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P2B49 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.