What does it mean?
P1514 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: ISC Solenoid Valve Signal No. 3 Circuit Malfunction (low input) .
Symptoms
- Check engine light on with an idle that will not hold steady
- Idle sags below normal and can drop far enough to stall
- Stalling when lifting off the throttle or when stopping
- No idle-up with the A/C compressor or heavy electrical load
- Rough running for the first minute after a cold start
- Slow return to idle after a gear change
Likely causes
- Short to ground on the channel 3 control wire, often at a chafe point near the intake
- Shorted turns in the winding of that solenoid channel
- Moisture or oil in the solenoid connector linking terminals together
- Poor supply or a corroded ground shared by the idle control circuit
- Damaged harness section after previous work around the throttle body
- Failed module driver on that output
How to fix it
- Note whether channels 1 and 2 also have codes, which would point at a shared supply or ground
- Unplug the solenoid and see whether the channel still reads low with the ignition on
- Measure the resistance of channel 3 and compare it with the other windings
- Check the control wire for a short to ground with both ends disconnected
- Perform a voltage drop test on the solenoid supply and ground
- Repair the harness or replace the idle speed control solenoid if the winding is out of specification
- Clean the throttle body while access is easy, then relearn the idle values