I have a 96 gmc k1500 I get the p1351 code every
now and then the motor is new along with
everything that touches it except for the brackets
that hold the a/c ect on to the motor distributor
and all ignition parts are new I changed the icm
also. I was wondering if anyone knew what would
make the icm have high voltage
unfortunately it could still be the icm. a bad connection, or a wiring short somewhere. Does your truck have long crank times to start? if so, It could be a fuel related issue. sounds crazy but it can happen. If you are having this issue it wouldn't hurt to check the fuel pressure to make sure it is within specs.
Possible causes p1351:>.......... - Faulty Ignition Control Module - Ignition Control Module harness is open or shorted - Ignition Control Module circuit poor electrical connection What does this mean? What does this mean? When is the code detected? The Powertrain Control Module (PCM) detects an open in the Ignition Control Module (ICM) Possible symptoms - Engine Light ON (or Service Engine Soon Warning Light) P1351 Gmc Description The Ignition Control Module (ICM) has independent power and ground circuits. The circuits between the ICM and the Powertrain Control Module (PCM) consists of the following circuits: -The ignition control (IC) timing signal -The IC timing control -The low resolution engine speed signal -The medium resolution engine signal -The camshaft position signal -The low reference The ICM sends 3X signals to the PCM, and controls the timing advance during engine cranking. The timing advance changes to PCM control after the following actions occur: The PCM receives the second 3X signal The PCM applies 5 volts to the ignition control (IC) timing signal circuit. The ICM monitors the CKP sync signal when the engine is cranking. The CKP sync signal is passed from the CKP sensor to the ICM on the CKP sensor 2 signal circuit. The CKP sync signal is used to determine the correct cylinder pair and initiate the ignition coil firing sequence. The 18X reference pulses are passed from the CKP sensor to the ICM on the CKP sensor 1 circuit. The 18X reference pulses are used for fuel injection and ignition control. After the ICM receives both signals, the ICM passes the 18X and 3X reference signals to the PCM. The CMP and the CKP sensors share a 12 volt reference and low reference circuit. The CKP sensor consists of the following circuits: -A 12 volt reference -A low reference -A CKP sensor 1 signal -A CKP sensor 2 signal
just thought I would ad that the reason the fuel could be an issue is if the truck wont hold fuel pressure then it is a leaky injector causing longer crank times co clear out excess fuel. this can cause a false 1351 code. If that's not the issue the I think rowe covered just about everything else!
So I would start by checking grounds.
And nothin wrong with verifying the fuel pressure as mike suggests. 56 to 63 lbs it should be..
fuel pressure should "hold" for a while key off. I bet you are on the right track though a bad ground could also throw that code.
Thanks for the help guys I'll get to checking some stuff out it doesn't take long to start might be a loose ground or something
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