P1518 – Intake Manifold Runner Control Fault Stuck Open (Ford, Lincoln, Mercury)

Mia

By Mia (Contact Me)
Last Updated 2017-05-03
ASE Master Tech

Trouble CodeFault LocationProbable Cause
P1518 Main Relay Circuit Short to B+ (AUDI, VOLKSWAGEN) Throttle Actuator Control Module Performance (BUICK, CADILLAC, CHEVROLET, GMC) Intake Manifold Runner Control Fault Stuck Open (FORD, LINCOLN, MERCURY) Commanded Versus Actual Throttle Position Correlation Large Step Open (ISUZU) VTCS Stuck Open Dual Plane Intake System Bank 1 (MAZDA) Starter Switch Circuit Low Input (SUBARU)

We recommend Torque Pro

What Does Code P1518 Mean?

Many modern vehicles use an intake manifold runner control (IMRC) system to improve engine performance and fuel economy. This design uses a solenoid controlled actuator (or module) to open and close the intake manifold butterfly valves. Adjusting the valves allows for variation of the intake runner length and improved volumetric efficiency. The actuator is controlled by the powertrain control module (PCM) based on inputs from the throttle position sensor (TP) and crankshaft position sensor (CKP).

Image result for imrc actuator ford f150

A typical IMRC actuator

(Courtesy: justanswer.com

Code P1518 is set when the PCM detects a problem with the intake manifold runner control system.

 

What are the common causes of code P1518?

  • Mechanical problem with the intake manifold or linkage
  • Failed IMRC actuator
  • Wiring problems
  • Faulty PCM

What are the symptoms of code P1518?

Symptoms associated with code P1518 may include poor engine performance and an illuminated check engine light.

How do you troubleshoot code P1518?

Start by visually inspecting the IMRC actuator and linkage. Look for damaged wiring, loose connections, binding linkage, etc. Repair as needed. Next, check for technical service bulletins (TSBs) about the concern. If no problems are found, move forward with a sequential diagnosis of the system. Refer to the manufacturer’s service information for the exact diagnostic process.

It’s a good idea to obtain the factory wiring diagram before proceeding with diagnosis. Autozone offers free online repair manuals for many vehicles under their repair help section (http://www.autozone.com/repairinfo) and ALLDATA offers single vehicle subscriptions (http://www.alldata.com/oe-info-student-and-diyer).

Test the power side of the circuit

Remove the IMRC actuator connector. Turn the vehicle ignition on and use a test light to check for power to the IMRC. To do this, connect a test light between the battery negative terminal and the IMRC B+ terminal on the harness side of the connector. The light should illuminate. If it does not, there is a problem on the power side of the circuit. Consult the factory wiring diagram and repair the power side of the circuit as necessary.

Capture2

A typical IMRC wiring diagram.

(Courtesy: ALLDATA)

Check the ground side of the circuit

Remove the IMRC actuator connector. Turn the vehicle ignition off and use a test light to check for IMRC ground. Connect the test light between the battery positive terminal and the IMRC ground terminal on the harness side of the connector. The light should illuminate. If it does not, there is a problem on the ground side of the circuit. Consult the factory wiring diagram and repair the ground side of the circuit as necessary.

Check the signal and monitor portions of the circuit

Remove the IMRC actuator connector. Use a digital multimeter set to ohms to check for continuity between the PCM and IMRC actuator. To do this, connect the meter between the IMRC signal terminal on the PCM and the signal terminal on the harness side of the IMRC connector. The meter should read a numeric value. If the meter read out of limits (OL) there is an open circuit. Consult the factory wiring diagram and repair the power side of the circuit as necessary.

If the circuit between the PCM and IMRC actuator is good, you’ll want to check that the PCM is supplying power to the IMRC. To do this, turn the ignition on and set the meter to read volts. Connect the negative meter lead to the battery ground terminal and the positive meter lead to the IMRC signal terminal on the PCM. Command the IMRC actuator on using an OEM equivalent scan tool. The meter should read around 5 volts. If it does not, there is a problem with a PCM or its programming. However, PCMs rarely go bad, so it’s a good idea to double check your work up to this point.

To test the monitor portion of the circuit, remove the IMRC actuator connector. Use a digital multimeter set to ohms to check for continuity between the PCM and IMRC actuator. To do this, connect the meter between the IMRC monitor terminal on the PCM and the monitor terminal on the harness side of the IMRC connector. The meter should read a numeric value. If the meter read out of limits (OL) there is an open circuit. Consult the factory wiring diagram and repair the power side of the circuit as necessary.Capture3A typical IMRC connector diagram.

(Courtesy: ALLDATA)

Check the actuator

Check the actuator by commanding it on with an OEM equivalent scan tool. If everything has tested OK up to this point and the actuator does not move, the actuator is probably faulty and should be replaced.

Codes Related to P1518

  • DTC P1516: Intake Manifold Runner Control Input Error Bank 1
  • DTC P1517: Intake Manifold Runner Control Input Error Bank 2
  • DTC P1519: Intake Manifold Runner Control Fault Stuck Closed
  • DTC P1520: Intake Manifold Runner Control Circuit Fault

 

 

Other Manufacturer Specific Definitions for P1518

Throttle control module/engine control module (ECM) -communication malfunction (GM)
Intake Manifold Runner Control Fault Stuck Open (Ford)
Engine control relay - short to positive (Volkswagen)
Engine control relay - short to positive (Audi)
Throttle Actuator Control Module Performance (Buick)
Throttle control module/engine control module (ECM) -communication malfunction (Cadillac)
Throttle control. module/engine control module(ECM) -communication malfunction (Chevrolet)
Throttle control module/engine control module (ECM) -communication malfunction (Hummer)
Throttle control module/engine control module   (ECM) – communication malfunction (Isuzu)
Intake manifold air control system – valve stuck open (Land Rover)
Intake manifold runner control (IMRC) module -malfunction, stuck open (Lincoln)
Intake manifold air control – stuck open (Mazda)
Intake manifold runner control (IMRC) module -malfunction, stuck open (Mercury)
Throttle control module/ECM -communicationmalfunction (Pontiac)
Starter motor switch – circuit malfunction (Saab)
Starter motor switch – circuit malfunction (Subaru)

BAT Team Discussions for P1518

  • 2001 ford windstar DTC P0171
    Can you please repost the pdf of tsb 03-16-1? Above it says that it "is regarding both P0171 and P0174 (1999-2001 ONLY)." I have a 2003 Windstar. Does this even apply for code P0174 on my van? If not, can someone help with P0174 on 2003? In addition to P0174, I am receiving P1518 (IMRC stuck open)....
  • 99 Taurus Problems
    I have a 99 Taurus SES that has a couple nagging issues that i was hoping to get some help on.... The first is a rattling noise that I notice when the car is cold started. I can only hear it from inside the car if I have the windows down, and sounds like it is coming from under the car. The rattl...
  • 03 Silverado Battery not charging message
    Condition Some owners may comment that the Check Engine Light is illuminated and there is no driveability concern. Upon investigation, the technician may find codes P0120, P0220, P1516 or P1518. Also, technicians may note that low voltage codes P0562, P0563, P1637 or P1638 have been set. Cause The ...
  • 2004 grand prix P0496
    Here is some info on it that might help you...Jim............DTC P0496 SYSTEM DESCRIPTION This DTC tests for undesired intake manifold vacuum flow to the evaporative emission (EVAP) system. The control module seals the EVAP system by commanding the EVAP canister purge solenoid valve OFF and the E...
  • dtc's wont clear could my pcm need a flash update?
    p1518 could affect mixture... sorry I cannot find a troubleshooting tree for this code.......