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1999 Chevy Tahoe P1345 Code: Diagnosis After O2 Sensor, Cat, and Injector Replacement at 165,000 Miles

Model: 99 Chevy Fault Code: P1345 Posted: 2007-07-08 11:37

I own a 1999 Chevrolet Tahoe with a Vortec 350 engine. Recently, I replaced all oxygen sensors, both catalytic converters, and the MPI injector assembly (including the fuel pressure regulator). The vehicle had been running smoothly prior to these repairs and has now developed severe starting issues—barely starts and fails to idle properly. A P1345 diagnostic code is now appearing. I've driven approximately 400–500 miles since completing the work, so I'm skeptical that the crankshaft position (CKP) sensor failed suddenly. Could a timing issue be the root cause? What should I check first to diagnose this problem accurately? The P1345 code indicates a malfunction in the crankshaft position sensor or related timing components. Given my recent work on the intake manifold and fuel system, I'm wondering if any of these modifications could have inadvertently affected engine timing or sensor readings.

Related fault codes

P1345

Comments (4)

Anonymous 2007-07-08 12:14

Why would you rule out a failing crankshaft position (CKP) sensor? Unless the timing was intentionally adjusted during intake work, how could it go out of time? And why does the P1345 code only appear after nearly 500 miles of driving?

Anonymous 2007-07-08 18:02

I'm not saying the crank sensor is definitely bad—just wondering if there are known conditions under which the P1345 code appears falsely or due to other factors. For example, could a loose distributor clamp cause a shift in distributor rotation, leading to timing misalignment? Given that I recently performed several engine-related repairs, it seems plausible that one of these actions might have affected sensor readings rather than a sudden CKP failure. I left the vehicle at work Friday and won’t be back until tomorrow. I’m doing some research before returning—any insights would be greatly appreciated.

Anonymous 2010-01-21 20:45

I have the same issue on my 1999 Tahoe. After replacing spark plugs and the crankshaft position sensor, the truck now won’t start at all and has not started in four days. This suggests a possible timing or sensor-related failure post-repair.

Anonymous 2010-01-29 13:15

My 1999 Tahoe came back from the mechanic with a new cap, rotor button, and Bosch platinum spark plugs installed. The mechanic also replaced the camshaft position sensor and discovered that the distributor was 38 degrees out of time. I have owned this truck for seven months and had never removed the distributor before—how it got out of time is beyond me. This issue only started in December, which aligns with a timing-related failure after recent maintenance.