If the fuel relief valve is stuck open would it possibly throw a P1316 code?

Thanks Alex

 

Very doubtful. Low fuel pressure/volume would not cause an electrical code for the injector/IDM wiring. The PCM has no real way of monitoring fuel pressure. Low fuel volume could, however, affect injector ICP and possible throw a different code.

 

DIAGNOSTIC TROUBLE CODE (DTC) P1316 INDICATES THAT CODES ARE STORED IN THE IDM

Possible causes:

a. Injector(s) or circuit(s)

b. Open or shorted IDM enable circuit

c. Open/short in EF circuit

d. Open/short in FDCS circuit

e. IDM relay

f. IDM powering circuits

g. IDM

h. PCM

Check for other codes.

Key on, engine off. (KOEO)

Perform KOEO On-Demand Self-Test.

P1316 OR P1670, CHECK FOR AN INTERMITTENT OPEN CIRCUIT

KEY OFF.

Install breakout box, leave PCM disconnected.

Disconnect IDM.

Check for intermittent open in the following circuits:

Measure resistance on (FDCS) Circuit 821 (BR/O) between IDM connector Pin 17 and PCM Test Pin 95.

Measure resistance on (EF) Circuit 818 (GY/W) between IDM connector Pin 4 and PCM Test Pin 48.

Grasp the harness close to the IDM connector. Wiggle, shake the harness while working your way back to the PCM, while looking for a spike on the DVOM.

Description The IDM provides the EF output signal to the PCM to confirm that proper timing/duration of fuel delivery command signal (FDCS) was received. Additionally, the EF signal is used to send diagnostics of the IDM and injectors (electrical) to the PCM.

DTC Description

P1668 = PCM-IDM diagnostic communication error

P1670 = Electronic feedback signal not detected

P1316 = Indicates that IDM DTCs are stored within the IDM

DTC P1668 and P1670 indicates that a communication error has occurred between the PCM and the IDM.

Possible causes:

a. Open fuse

b. IDM relay

c. Open or shorted IDM enable circuit

d. Open/short in EF circuit

e. Open/short in FDCS circuit

f. IDM powering circuits

g. PCM

h. Check for other codes.

KOEO:

Perform KOEO On-Demand Self-Test and retrieve Continuous DTCs.

CHECK CIRCUIT 818 (GY/W) FOR OPEN

Install breakout box; leave PCM disconnected.

Disconnect the IDM harness connector.

Measure resistance on Circuit 818 (GY/W) between PCM Test Pin 48 and IDM harness connector Pin 4.

Key on, engine off. Measure for voltage on Circuit 818 (GY/W) between PCM Test Pin 48 and battery ground.

Turn ignition switch to OFF. Measure resistance on Circuit 359 (GY/R) between PCM Test Pin 91 and IDM connector Pin 2.

CHECK IDM POWER

PCM connected, IDM disconnected.

KOEO. Measure voltage between IDM connector Pin 14 and battery ground.

CHECK IDM GROUND

KEY OFF. Measure resistance between IDM connector Pin 26 and battery ground.

 

I have my work cutout for me and thanks.

 

That P1316 codes should not be related to fuel pressure at all. Get a scan tool plugged in that can do an injector buzz test. That should tell you what is causing the P1316 code. All that codes means is that there are IDM codes detected. Doing the buzz test will normally pull those codes.