What does it mean?
P1458 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Evaporative Emission (EVAP) System Leak Detection Pump Pressure Sensor Performance .
Symptoms
- MIL on with the EVAP monitor never completing
- Pump may run but the pressure value stays flat in live data
- Additional EVAP codes, sometimes reporting leaks that do not exist
- Fuel vapour smell only if there is a genuine leak
- No effect on engine performance
Likely causes
- Sensor inside the pump assembly drifted, sticking or failed
- Blocked pump filter or vent path so no pressure change can be produced
- Diaphragm in the leak detection pump split or leaking, giving no pressure rise
- Corroded or water damaged connector at the pump assembly
- Open, shorted or high resistance wiring in the sensor circuit
- Large leak elsewhere in the EVAP system preventing any pressure build up
- Water frozen inside the pump in very cold conditions
How to fix it
- Command the leak detection pump and watch its pressure value in live data to see whether it changes at all
- Inspect the pump connector and harness under the vehicle for corrosion, water and impact damage
- Remove and inspect the pump filter and vent hose for dirt, insects and blockage
- Verify supply voltage and ground at the pump assembly with the key on
- Test the sensor circuit wiring for continuity and shorts back to the PCM
- Check the rest of the EVAP system for a large leak first, since the pump cannot build pressure into an open system
- Replace the leak detection pump assembly when its internal sensor is at fault, then rerun the EVAP monitor