Sorry for the delay!
P1518 Intake Manifold Runner Control Stuck Open
IMRC connector is damaged IMRC Monitor signal circuit shorted to groundIMRC actuator has failedPCM has failed
We are going to have to run some checks in order to figure out what is going on. Check the voltage to the Intake Manifold Runner Control actuator on top of the front valve cover. Battery voltage should be on the Green/White wire at the actuator. With the actuator unplugged and the key on, check for 5 volts on the Black/Blue wire in the connector. If that checks out ok, then back probe the Black/Red wire with a jumper wire, and install a voltmeter on the Black/Blue wire, with the voltmeter ground lead to any good ground. Then, with the key on and the actuator connected, ground and unground the Black/Red wire using the jumper wire. Look for the actuator cable to pull in and open the levers on the intake manifold when the Black/Red wire is grounded, and for the cable and levers to release when the Black/Red wire is ungrounded. Verify that the levers in the intake manifold move freely. Also, monitor the voltage on the Black/Blue wire as the actuator cable pulls in and releases. When the actuator is released, the voltage should be 5 volts, and when it pulls in, the voltage should drop to slightly less than 1 volt.
Since I ma not there ot test if for you, I don't know what the results are or what they are going to be when the test that I gave you is run. It is possible for the intake to intake manifold runner to be bad. However, the Intake Manifold Runner Control (IMRC) Actuator goes bad a lot as well. Just be sure to check everything before replacing the intake manifold.
I DO hope you found my Answer to be helpful regarding your vehicles condition. IF SO-please hit **ACCEPT** as you read this Answer, in order that I may receive credit for my time, thanks. BONUSES & Positive Feedback Most appreciated!
Please Note: I receive ZERO Credit until & unless you choose to ACCEPT my well thought-out Answer.