P1506 FORD, JAGUAR, LINCOLN, MAZDA, MERCURY: IDLE AIR CONTROL OVERSPEED ERROR
POST UPDATED IN February, 2023
P1506 Code failures by brands
Description of DTC code P1506
The Idle Air Control (IAC) Valve assembly is intended to control engine idle speed and provide a dash function. This assembly measures the intake air passing around the throttle plate through a bypass, which is located on the inside of the IAC Valve assembly and throttle body.
The PCM (Powertrain Control Module) determines the expected idle speed or bypass air. It signals the IAC assembly using a certain duty cycle. In response, the valve is moved to a position that allows the amount of bypass air to be regulated. This controller also monitors the engine rpm and accordingly increases or decreases the valve duty cycle to achieve the desired rpm.
The P1506 OBDII diagnostic code P1506 is stored after the PCM detects an engine idle speed, which exceeds the expected revolutions. This error can be defined as the engine’s idle speed being out of specification.
Symptoms of fault code P1506
- Check Engine Lamp ON.
- Irregular idling operation.
Causes of OBD2 P1506
Reasons for setting the P1506 OBD2 DTC P1506 OBD2 code:
- The Idle Air Control Valve wires or connectors may be damaged.
- The IAC valve may be in poor condition.
- There may be intake leaks.
- Possibly the Positive Crankcase Ventilation Valve (PCV) is defective.
Possible solutions of the DTC code P1506
Steps to solve the P1506 OBDII fault code:
- Consult the Technical Service Bulletins.
- Verify that there is no damage to the wiring or connectors related to the IAC Valve If you find common damage, make repairs.
- Measure the idle air control valve circuit voltages to verify that they match the manufacturer's specifications. If deficiencies in the voltages are found, make the appropriate corrections.
- Check that there are no intake leaks. If it is the case, make the corresponding adjustments.
- If after performing the above-mentioned repairs you still get the P1506 code, it is likely that the IAC or PCV valve is faulty. In this case, you should consult the diagnostic steps for both valves, and if you determine that they are damaged, make the appropriate corrections.
