What does it mean?
P1502 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Fuel Pump Relay Circuit Short to B+ .
Symptoms
- MIL on
- The relay never energises, because the coil sees battery voltage on both sides and no current can flow
- Fuel pump does not prime with the key on, and no pump noise is heard from the tank
- Long cranking or a complete no start, with fuel pressure staying at zero while cranking
- Engine may start and then stall as soon as residual rail pressure is used up
- The circuit fuse or the module output driver can be damaged by the fault current
- The fault is usually detected the moment the module first commands the relay on
Likely causes
- Fuel pump relay control circuit shorted to battery voltage
- Insulation breakdown inside the relay, letting the switched B+ side reach the coil control pin
- Melted harness insulation where the wire runs near a power feed or a hot component
- Corrosion bridging a power pin to the control pin inside the relay socket
- Incorrect relay fitted with a different internal pin layout
- Aftermarket wiring tapped into the fuel pump circuit
- Module driver damaged by the applied voltage
How to fix it
- Disconnect the relay and check the control wire for voltage with the key off
- Inspect the relay socket for corrosion and melted or discoloured terminals
- Confirm the correct relay part is fitted and fully seated
- Follow the harness looking for melted or abraded insulation near power leads
- Check for non factory connections spliced into the circuit
- Repair the shorted wire, and replace the relay if it tests internally shorted between its coil and contact sides
- Confirm the pump primes for the normal few seconds and then shuts off