What does it mean?
P1308 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Acceleration Sensor Low Input .
Symptoms
- MIL (check engine lamp) on together with ABS and stability warning lamps
- Stability and traction control switched off, with the warning lamps on from key on
- Hill-hold and similar assistance functions unavailable
- Some vehicles hold a conservative shift schedule or limit engine torque
- No change in the live sensor value when the vehicle accelerates or brakes
Likely causes
- Signal wire shorted to ground or broken
- Loss of the supply or reference voltage feeding the sensor
- Internally failed sensor stuck at the bottom of its range
- Water and corrosion inside the sensor connector, common on underfloor or chassis mounted units
- High-resistance sensor ground shifting the whole signal downwards
- Harness damage where it crosses from the body to the chassis-mounted sensor
How to fix it
- Read the live signal: a value pinned at the bottom of the scale that never moves confirms a low circuit
- Unplug the sensor and measure the supply voltage and ground at the connector, key on
- With the sensor unplugged, check the signal wire for continuity and for a short to ground
- Briefly jumper the reference to the signal pin; if the module then reads high, the harness and module are good
- Inspect the connector for water, corrosion and pushed-back terminals, and reseal it if the design uses a boot or grommet
- Repair the wiring fault, or replace the sensor when the circuit checks good
- Run the zero-point calibration, clear the codes and verify all warning lamps stay off