What does it mean?
P1413 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Secondary Air Injector Pump Relay Control Circuit Signal Low .
Symptoms
- MIL on and the secondary air readiness monitor stays incomplete
- The air pump may run continuously after start up, or not run at all
- Rough or hunting idle during the first minute after a cold start
- Loud continuous whirring from the pump when it should already have shut off
- Emissions test failure due to high hydrocarbon output on cold start
Likely causes
- Control wire between the PCM and the relay coil shorted to ground
- Relay coil internally shorted or with very low winding resistance
- Water intrusion into the relay socket, common where the box sits low in the engine bay
- Corroded relay terminals or a relay pushed only partway into its socket
- Rubbed through insulation where the harness passes a metal edge or bracket
- Poor ground reference for the air pump circuit, which pulls the signal line down
- PCM driver failure, only after the external circuit is cleared
How to fix it
- Pull the relay and inspect the socket for water, green corrosion and burnt terminals
- Measure the relay coil resistance and compare both windings against specification
- Disconnect the relay and check the control wire to ground with the key on; a reading close to zero ohms means a short to ground
- Isolate the harness by unplugging the PCM connector and repeating the ground test on that wire
- Inspect the harness where it passes the exhaust manifold and body brackets for chafed insulation
- Verify the pump ground and power supply before condemning the relay
- Repair or replace the shorted section, fit a new relay if the coil is faulty, then perform a cold start test to confirm pump operation