Persistent Code 9
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Super Moderator : And A Texan
Joined: Feb 2007
Posts: 9,652
From: Katy, TX
The way I eventually convinced myself the ECU was likely the problem was disconnecting the B (middle) connector at the ECU and measuring the CYP sensor resistance (orange, pin 11 and white, pin 12 wires) from that point. I got values of ~820 ohms, nearly same as I got at every other connector stage of the wiring harness.
Since you've replaced the ECU, I would check the sensor resistance as described above to check for a wiring fault or sensor fault. If you get out of spec values (too low or high), check closer (right fender shock tower) to the distributor, and finally at the distributor connector. If you get good sensor resistance at all those points, it would suggest an ECU fault as I had.
good luck
Since you've replaced the ECU, I would check the sensor resistance as described above to check for a wiring fault or sensor fault. If you get out of spec values (too low or high), check closer (right fender shock tower) to the distributor, and finally at the distributor connector. If you get good sensor resistance at all those points, it would suggest an ECU fault as I had.
good luck
Joined: Feb 2023
Posts: 1
I’ve experienced Code 9 multiple times..
I have had a persistent code 9 (#1 Cylinder Position CYP Sensor Fault). This sensor is in the distributor.
Long story here. Several years ago, this code first appeared. I purchased a replacement distributor and problem was fixed for a long time, until this past summer, when problem reappeared (Code 9). Symptoms are rough starting, difficult start particulary on wet damp conditions. Once warmed and running, the symptoms disappear and CEL will not come on when started.
I now suspected a wiring fault, but checked sensor (good), and checked sensor from ECU connector in cabin, again good.
Not believing my ECU could be bad, I bought another distributor and again the problem seemed cured for a short time, but has again appeared after not using car for several days (now a spare to drive when I'm repairing something else).
I now believe my ECU must be intermittent w/ a cracked circuit or component.
My question: Does anybody see another possible fault I could investigate or diagnostic to perform?
Thanks
Long story here. Several years ago, this code first appeared. I purchased a replacement distributor and problem was fixed for a long time, until this past summer, when problem reappeared (Code 9). Symptoms are rough starting, difficult start particulary on wet damp conditions. Once warmed and running, the symptoms disappear and CEL will not come on when started.
I now suspected a wiring fault, but checked sensor (good), and checked sensor from ECU connector in cabin, again good.
Not believing my ECU could be bad, I bought another distributor and again the problem seemed cured for a short time, but has again appeared after not using car for several days (now a spare to drive when I'm repairing something else).
I now believe my ECU must be intermittent w/ a cracked circuit or component.
My question: Does anybody see another possible fault I could investigate or diagnostic to perform?
Thanks
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