P0343 -What Does It Mean? (1999-2006 V8 Silverado, Sierra, Suburban, Tahoe, Yukon)

In this tutorial, I'll explain the meaning of trouble code P0343: Camshaft Position (CMP) Sensor Circuit High Voltage.

I'm also going to explain how to troubleshoot and repair the cause of this trouble code.

You can find this tutorial in Spanish here: Código P0343 ¿Qué Significa? (1999-2006 V8 Silverado, Sierra, Suburban, Tahoe, Yukon) (at: autotecnico-online.com).

APPLIES TO: This tutorial, on the P0343 OBD II trouble code, applies to the following vehicles:

Chevrolet:

• Silverado (1500, 2500):
  • 4.8L, 5.3L: 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Silverado (2500):
  • 6.0L: 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Suburban (1500):
  • 5.3L: 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Suburban (2500):
  • 6.0L: 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Tahoe:
  • 4.8L, 5.3L: 2000, 2001, 2002, 2003, 2004, 2005, 2006

GMC:

• Sierra (1500, 2500):
  • 4.8L, 5.3L: 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Sierra (2500):
  • 6.0L: 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Yukon:
  • 4.8L, 5.3L: 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Yukon XL (1500):
  • 5.3L: 2000, 2001, 2002, 2003, 2004, 2005, 2006
• Yukon XL (2500):
  • 6.0L: 2000, 2001, 2002, 2003, 2004, 2005, 2006

RELATED TROUBLE CODES:

• P0341 -What Does It Mean? (1999-2006 V8 Silverado, Sierra, Suburban, Tahoe, Yukon).
• P0342 -What Does It Mean? (1999-2006 V8 Silverado, Sierra, Suburban, Tahoe, Yukon).

RELATED WIRING DIAGRAMS:

• CMP And CKP Sensor Circuit Diagram (1999-2006 V8 Silverado, Sierra, Suburban, Tahoe, Yukon).

What Does Trouble Code P0343 Mean?

The camshaft position sensor is designed to produce a voltage signal (1X CMP signal) that corresponds to the rotation of a tooth on the camshaft.

The 1X CMP signal is then sent directly to the fuel injection computer.

A trouble code P0343: Camshaft Position (CMP) Sensor Circuit High Voltage is set when:

• The CMP sensor's voltage signal stays stuck at a high value when it should be lower.
• A problem has occurred with the CMP sensor's wiring that is causing a high voltage value to be transmitted to the fuel injection computer.

Common Symptoms Of A P0343 Trouble Code

A failure of the camshaft position sensor will cause one or more of the following symptoms:

• Extended cranking time (engine takes longer than usual to start).
• Lack of power when accelerating engine under load.
• Engine may stall after starting.
• Check engine light illuminated on the instrument cluster.
• Trouble code P0343 registered.

What Does The Camshaft Position Sensor Do?

The camshaft position sensor monitors a tooth on a reluctor wheel on the back of the camshaft.

As the camshaft turns and the tooth (on the reluctor wheel) passes under the camshaft position sensor, it produces a pulsing ON/OFF voltage signal .

This ON/OFF voltage signal is called the 1X CMP signal in GM's service literature.

Thru' the 1X CMP signal, the fuel injection computer is able to monitor and know the position and rotation of the camshaft as the engine runs.

The fuel injection computer then uses the camshaft position sensor signal info to:

• Determine if the pistons are on their compression (firing) or exhaust stroke.
• Fine tune ignition timing and fuel injection.

What Causes A P0343 Trouble Code?

Generally, a bad camshaft position sensor is the culprit behind the P0343, but not the only one.

Other things that can cause a P0343 trouble code are:

• Damaged CMP sensor connector making a poor connection.
• Wiring harness problem causing tension on the CMP sensor connector.
• CMP signal wire has a short-circuit problem to voltage.

How To Diagnose And Repair A P0343 Trouble Code

Troubleshooting and repairing the cause of a P0343 trouble code involves:

• Inspecting the CMP sensor's connector.
• Inspecting the CMP sensor connector's wiring.
• Testing the CMP sensor to see if it's producing a 1X CMP signal.

Once you've inspected (and found no problems) with the CMP sensor's connector and its wires, testing the camshaft position sensor involves:

• Checking that the CMP sensor is receiving 12 Volts.
• Checking that the CMP sensor is getting Ground (from the fuel injection computer).
• Making sure that the CMP sensor is producing its CMP 1X signal.

The 3 above mentioned tests can be done with a simple multimeter.

You can correctly conclude that the CMP sensor is bad, and needs to be replaced, if:

• The CMP sensor is receiving 12 Volts from the fuel injection computer.
• The CMP sensor is receiving Ground from the fuel injection computer.
• The CMP sensor IS NOT producing its CMP 1X signal.

The following tutorial will help you test the camshaft position (CMP) sensor:

• Bench-Testing The CMP Sensor (1999-2006 V8 Silverado, Sierra, Suburban, Tahoe, Yukon).

Where To Buy The CMP Sensor And Save

The following link will help you comparison shop for the AC-Delco camshaft position sensor:

NOTE: The AC-Delco brand is the original equipment part for the Chevrolet and GMC vehicles.

More Silverado, Sierra, Suburban, Tahoe, And Yukon Tutorials

You can find a complete list of V8 Chevrolet Silverado (Sierra, Suburban, Tahoe) and GMC Sierra (Yukon, Yukon XL) tutorials in this index:

• GM 4.8L, 5.3L, 6.0L Index Of Articles.

Here's a small sample of the tutorials you'll find in the index:

• Resistance Specifications Of The TAC Electronic Throttle Body.
• How To Test The GM Accelerator Pedal Position (APP) Sensor 2.
• How To Test The MAF Sensor (GM 4.8L, 5.3L, 6.0L, 8.1L).
• Blown Head Gasket Test (GM 4.8L, 5.3L, 6.0L).