1996 GMC Sierra P1345 Cam-Crank Correlation

1996 GMC Sierra


  • 5.0L (305 cubic inches) V8
  • Horsepower: Approximately 220 hp
  • Torque: Approximately 285 lb-ft


  • Four-speed automatic transmission

Fuel Economy:

  • City: 15-18 mpg
  • Highway: 20-23 mpg

Troubleshooting and Resolving P1345 Code on a 1996 GMC Sierra with 5.0L Engine

If you own a 1996 GMC Sierra with the 5.0L engine, discovering the P1345 trouble code can cause concern. In this comprehensive guide, we’ll delve into the specifics of the P1345 code, its potential causes, and practical steps to diagnose and resolve the issue, ensuring your Sierra runs smoothly.

What is P1345?

P1345 is a diagnostic trouble code (DTC) that relates to the Camshaft Position Sensor (CMP) or Crankshaft Position Sensor (CKP) in the engine. Specifically, it indicates a fault in the correlation between the crankshaft and camshaft positions.


Causes of P1345 on the GMC Sierra:

  • Timing Chain Issues: A worn or misaligned timing chain can disrupt the synchronization between the crankshaft and camshaft, triggering the P1345 code.
Timing Chain

The timing chain in a vehicle plays a crucial role in the proper functioning of the engine. Its primary purpose is to synchronize the rotation of the crankshaft and the camshaft.

  • Faulty Camshaft Position Sensor: The camshaft position sensor plays a crucial role in providing data to the engine control module (ECM). A malfunctioning sensor can lead to improper timing and trigger the P1345 code.
Camshaft Position Sensor

The camshaft position sensor (CMP sensor) in a vehicle is a crucial component of the engine control system. Its primary purpose is to monitor the position and speed of the camshaft.

  • Crankshaft Position Sensor Problems: Similar to the camshaft position sensor, a faulty crankshaft position sensor can result in a misalignment between the crankshaft and camshaft positions.
Crankshaft Position Sensor

The crankshaft position sensor (CKP sensor) is a critical component in a vehicle’s engine management system. Its primary purpose is to monitor the position and rotational speed of the crankshaft.

  • Distributor Problems: In older vehicles like the 1996 GMC Sierra, a distributor is responsible for routing high-voltage power from the ignition coil to the spark plugs. Issues with the distributor can affect timing and trigger the P1345 code.

In older vehicles, distributors were a key component in the ignition system. The primary purpose of a distributor is to distribute high-voltage electrical power to the spark plugs in the correct firing order.


Symptoms of P1345:

  1. Check Engine Light (CEL): The most obvious symptom is the illumination of the Check Engine Light on the vehicle’s dashboard.
  2. Rough Running or Stalling: The engine may run rough or stall intermittently. This is because the camshaft position sensor helps the engine control module (ECM) determine the proper timing for fuel injection and spark ignition.
  3. Hard Starting: Difficulty starting the engine, especially when it’s warm or cold, can be a symptom of a faulty camshaft position sensor.
  4. Poor Fuel Economy: A malfunctioning camshaft position sensor can affect the engine’s efficiency, leading to decreased fuel economy.
  5. Reduced Performance: The engine may exhibit reduced performance, and you may notice a lack of power during acceleration.
  6. Poor Idle Quality: Unstable or rough idling can be a consequence of incorrect camshaft position information reaching the ECM.

Diagnosing P1345 on the GMC Sierra:

  1. Use Diagnostic Tools: Invest in an OBD-II scanner to retrieve the specific P1345 code and additional information from your vehicle’s ECM. This data will help you pinpoint the root cause.
  2. Inspect Timing Components: Examine the timing chain for signs of wear, misalignment, or damage. Address any issues found during the inspection.
  3. Check Camshaft and Crankshaft Sensors: Test the camshaft position sensor and crankshaft position sensor using a multimeter to ensure they are functioning correctly. Replace any sensors showing signs of malfunction.
  4. Examine the Distributor: Inspect the distributor for wear, carbon buildup, or other issues. Replace or repair components as needed.

Resolving P1345 on the GMC Sierra:

  1. Timing Chain Replacement: If wear or misalignment is detected during the inspection, replace the timing chain to restore proper synchronization.
  2. Sensor Replacement: Replace any faulty camshaft or crankshaft position sensors identified during testing. Ensure you use high-quality replacement parts.
  3. Distributor Repair or Replacement: If distributor issues are found, repair or replace the distributor to ensure proper ignition timing.


Addressing the P1345 code on your GMC Sierra requires a systematic approach to diagnose and resolve the underlying issues. Regular maintenance and timely repairs will keep your Sierra running smoothly, ensuring optimal performance for years to come.

Remember, always consult with a qualified GMC mechanic or seek professional assistance if you’re unsure about the diagnosis or resolution to avoid further complications.

(Online Auto Tech is supported by readers like you. When you purchase through links on our site, we may earn an affiliate commission.)