P1345 Chevy: Crankshaft position- camshaft position correlation

Vehicle owners who are not mechanics have a major problem in common – the difficulty of getting rid of certain DTCs. The P1345 code is definitely one of these Diagnostic Trouble Codes.

Worry not. This article will dive deep into the P1345 code on GM (Chevrolet) vehicles. We will tackle an older Chevy engine model, specifically the 5.7 Vortec, in which this problem is highly prominent.

However, this knowledge is transferable and will help you fix your Chevy. There will be a few differences depending on the engine design and the types of ignition triggers. At the very end, you will be able to fix the problem yourself, if you are a little bit handy.

P1345 Chevy definition and meaning

Definition

Trouble code P1345 is a manufacturer-specific code defined as Crankshaft position-camshaft position correlation on General Motors vehicles.

Meaning

P1345 is a manufacturer-specific DTC, which means that diagnosing it will be different for different manufacturers. Moreover, the code may only apply to specific vehicles: Audi, Isuzu, Toyota, BMW, GM (Chevrolet and GMC), Lexus, Mazda, and Volkswagen.

The P1345 code on a Chevy or GMC truck will defer from the same code in another car model. From the table below, you can see the different definitions of the code that differ from the P1345 code on GM vehicles.

Trouble codeDefinitionManufacturer
1. P1345Variable Valve Timing Sensor – LH bank – circuit malfunctionLexus
2. P1345Radiator Ventilation, lower – electrical faultBMW
3. P1345Camshaft Position (CMP) sensor – signal malfunctionMazda
4. P1345Ignition amplifier, primary circuit 3 – short to groundVolkswagen
5. P1345CKP/CMP signals – signal malfunctionIsuzu

Regardless of the definitions, these codes have one thing in common – they indicate an ignition problem. As earlier stated, these codes defer due to the type of engine and ignition triggers used in each specific vehicle. However, they have another thing in common: the application of Camshaft Position Sensors (CMS) and Crankshaft Position Sensors (CKS).

The camshaft position sensor is a sensor in your vehicle. It provides the Engine Control Module (ECM) or Powertrain control module (PCM) as referred to in some vehicles, with the exact position of the camshaft lobes relative to the valve openings on each cylinder. This information will then be used by the Engine control module (ECM) to choose the best fuel injector timing.

On the other hand, there is the crankshaft position sensor (CKS), which is a sensor that provides a signal to the engine control module indicating the position of the crankshaft or crankshaft timing relative to the top dead center on the compression stroke of the cylinder number 1 in the engine.

These two sensors work together with the engine control module to control engine timing. These sensors will be in sync if everything is working properly. When the interrelation between the camshaft position sensor and crankshaft position sensors is out of sync for more than 1 or 2 degrees, the error code P1345 will be recorded.

The P1345 Chevy code may be caused by faulty CKS and CMS sensors, but in most cases, it results from a problem in engine timing. This confusion is done away with in newer vehicles whose engines adjust the timing themselves. In these newer vehicles, you will also receive a p0335 code and p0340, telling you that the CKS and CMS sensors are bad or malfunctioning.

List of OBD2 codes that relate to P1345 on Chevy

1. P0335 – Crankshaft Position Sensor ‘A’ Circuit malfunction

2. P0340 – Camshaft Position Sensor ‘A’ Circuit malfunction

Symptoms of P1345 on Chevy?

1.      Check engine light ‘ON’ – like other codes, this code will trigger the ‘check engine’ light and get stored in the vehicle’s memory system.

2.      Engine misfires above 1500 rpm – an engine may misfire if there is a problem with the distributor, resulting in the lack of enough current to ignite the spark plugs. The resulting trouble is a misfire. At higher speeds, the ECM usually tries to adjust valve lift. Therefore, engine misfiring may be an indication of your valve timing being off.

3.      Rough idling and stalling while driving – most engine problems such as these will deem your engine performance inefficient, resulting in the engine idling and stalling.

4.      Difficulty in starting the engine – an engine with poor timing will exhibit difficulties in starting up since the engine timing is crucial for its operation. Newer vehicles improved on this by having the engine time itself.

Causes of P1345 on Chevy?

1.      Loose, faulty, or bad camshaft position sensors and crankshaft position sensors (highly unlikely)

The CKS and CMS may be faulty if the p0335 code and/or p0340 codes are recorded too. A quick fix for this would be to replace the sensors or have a mechanic fix them. However, in the absence of these two codes, the problem will be located elsewhere.

2.      Stretched, slipped, or improperly installed valve timing chain

There may be an excessive free play on the valve timing chain and gear assembly that may result in the valve timing being off. This may be due to mechanical wear or improper installation.

3.      Incorrect distributor positioning or loose distributor rotor on the distributor shaft (most likely)

The distributor transfers current to the ignition coils for firing up the spark plugs. If it fails, it will not deliver current at the right time to the appropriate coil resulting in misfires and engine timing going off.

4.      Bad wiring connections causing simple electrical connection failures

Chafing, corroding, rubbing, or burning spots on melted wire insulation may result in connection problems. These types of wiring problems should be checked as a regular maintenance procedure.

How serious is the P1345 Chevy OBD2 code?

As much as you may get by without fixing this trouble code for a while, it is advisable not to. The engine will have trouble starting on multiple occasions, and it may also suddenly stop. These two scenarios are not any driver’s cup of tea. Moreover, the check engine light may end up staying on till you fix the problem.

How to diagnose and fix the code P1345 on Chevy?

Tools needed

1. OBD2 scan tool.

2. Electrical cleaner

3. Plastic bristle brush

4. Dielectric silicone grease

5. Digital Volt Ohm Meter (DVOM)

Method

We are specifically tackling a 5.7 Vortec engine here. You will need to check if there are any technical service bulletins (TBS) for your vehicle. This may save you time and money if the manufacturer has put out a fix for this specific problem.

1. You will first need an OBD scan tool to connect to the OBD port on your car. Use it to scan for all the stored codes to ensure you diagnose those other codes before the P1345.

2. Check for any corroded, burnt, or defective wiring in the connections around the CKS and CMS sensors. Pull the connectors apart and inspect the terminals inside. If they are corroded or burnt, you will have to clean them with an electrical cleaner and the brush listed above.

Let them dry. Apply dielectric silicone grease on the terminals before returning the sensors.

3. Check for any damages and faults on and around the CKS and CMS sensors. If any, you will need to replace them and see if the problem is solved. To see if the sensors are working correctly, you will need to use a Digital Volt Ohm Meter (DVOM). Test the 5V power supply circuit going to each sensor to ensure it is being powered up.

4. Clear the trouble codes from memory and see if the P1345 code returns. If it does, then the problem is elsewhere. Proceed to the next step.

5. Analyze the assembly of the timing chain and gear assembly to make sure there is no excessive free play. Fix the problem by adjusting the installation. You may also need to get spare parts for the affected components. If this does not fix the problem, then the last and final diagnosis will be a problem with the distributor.

A distributor may be loose or missing. It is responsible for current delivery to ignition coils in the correct firing order and correct time period. It contains a rotor, which may be loose in this case. On top of this, the gear inside of the distributor may be bad.

The distributor may need to be replaced, but if it is new and/or in good working condition, its positioning is probably off.

6. Using the scan tool, connect it to the OBD port on your vehicle with ignition OFF. Start the engine. From the scan tool, read the “Cam Retard Offset,” you will need to get your engine to 1000 rpm for accurate results.

7. A reading of +/-2 degrees of Zero is an indication of optimal timing. Otherwise, you will need to adjust the distributor. You can adjust it by loosening the bolt on the distributor while the engine is off. Connect scan tool and monitor the “Cam Retard Offset” reading. Start the engine and make sure it reaches 1000 rpm.

8. Adjust the positioning by turning the distributor clockwise if the reading is positive and anticlockwise if the reading is negative. Do this till the “Cam Retard Offset” reading is within +/- 2 degrees of Zero, finally solving the issue.

Tips to avoid P1345 in the Future

1. Perform regular preventive maintenance. Problems related to P1345 will be caught earlier.

2. Avoid driving through deep puddles because water will get into the distributor cap and short out.

FAQs

How do I know the distributor is not the problem for P1345 ?

If other codes such as p0335 and p0340 are saved, there is a high likelihood the problem lies elsewhere but directly or indirectly affects valve timing and its components.

What is the cost of diagnosing the P1345 Chevy code?

The charges vary depending on where you take your vehicle for repair. The charges average at around $75 to $150 an hour. Diagnosing the P1345 Chevy code will take approximately 1 hour.

What if all the solutions listed above do not fix the problem?

If you carefully follow all the steps above, the problem will be fixed. However, if it persists or other issues such as the engine not starting and misfires, you may have another component issue. Scan for the DTCs and see what the codes are indicating. Proceed from there.

Does this solution apply to the P1345 code in other vehicles apart from GM (Chevrolet and GMC truck)?

This solution is specific to GM and Chevrolet vehicles. Search for Technical Service Bulletins by your manufacturer for a detailed solution to different manufacturers.

What if I have the P1345 code, but the engine works fine?

This is a clear indication that symptoms will surely come after some time. Take your car for maintenance to fix it sooner rather than later.

Read More: Crankshaft vs. camshaft: The definite guide