How to Fix DTC P1345 on a 1998 Chevy S-10: Causes, Diagnosis, and Permanent Solutions

A code reader only displays stored trouble codes—it doesn’t communicate with the engine control module (PCM). A true scanner allows two-way communication, enabling diagnostics like adjusting sensor offsets. For P1345, accessing the correct 'window' on a scanner can help fine-tune cam and crank position correlation. For your 1998 Chevy S-10 with a 4.3L engine, it's best to consult a qualified technician for an accurate diagnosis—this may be easier and more cost-effective than purchasing or learning to use a scanner yourself. Also, check online automotive repair guides or local libraries for manuals on distributor alignment techniques, such as matching tick marks on the distributor gear to ensure proper timing.

Thanks for the response. I've been battling this issue for years—trying various fixes: replaced camshaft position sensor, crankshaft sensor, spark plugs, wires, coil, and ignition control module—all without success. I also changed to a high-volume oil pump at the same time as my distributor replacement due to vibration in the oil pressure gauge. The new distributor lasted only briefly before the drive gear stripped. After researching forums, I discovered that high-volume oil pumps may increase torque on the distributor shaft, leading to flexing—especially with plastic shafts common in older GM distributors. I switched back to a standard oil pump and replaced the gear, but P1345 persisted. Then I began analyzing the mechanical design: the weakest point in the distributor shaft is at the drive gear. Increased torque or resistance causes bending under load. Over time, heat and wear degrade plastic shaft integrity, leading to flexing. This flexing causes the distributor gear to shift relative to the cam gear—resulting in P1345 and P0300 codes, as well as eventual gear stripping. I suspect I replaced my distributor with a 'rebuilt' unit from a local parts store instead of a genuine new GM one. These remanufactured units often have degraded shafts due to prior wear—making them unreliable after 200,000+ miles. My solution: installed a new distributor with an aluminum shaft (part #SUM-850097 from Summit). All symptoms—including the P1345 code—are now resolved. I hope this helps others facing similar long-term issues on older S-10s.

This is a well-documented issue in older GM engines, especially with 4.3L V6 units and plastic distributor shafts. The root cause of P1345 isn't always sensor failure—it's often mechanical wear or improper torque loading on the distributor. For long-term reliability, avoid using remanufactured distributors with plastic shafts. Instead, opt for genuine OEM or high-quality aftermarket models featuring aluminum shafts that resist flexing under load. Always verify timing alignment and ensure no additional components (like high-volume oil pumps) are introducing extra torque to the distributor system. A proper diagnosis requires understanding both electronic and mechanical aspects of engine timing.

This issue is frequently overlooked in standard repair guides. Many users try replacing parts without addressing underlying mechanical design flaws. For a 1998 Chevy S-10 with P1345, the key takeaway: don't rely solely on sensor replacements or distributor swaps—especially if using rebuilt units from local stores. The plastic shaft in older GM distributors is prone to flexing under heat and load, leading to timing misalignment. A genuine aluminum-shaft distributor (e.g., Summit part #SUM-850097) resolves the issue by eliminating shaft flex. Combined with proper maintenance and avoiding high-volume oil pumps, this fix prevents both P1345 and related symptoms like gear stripping or engine vibration. This case highlights why accurate diagnosis matters—what looks like an electrical problem may actually stem from mechanical design flaws in older vehicles.