Mechanics

CAM SHAFT POSITION SENSOR

2000 Pontiac Grand Prix

Engine Mechanical problem
2000 Pontiac Grand Prix 6 cyl Two Wheel Drive Automatic 100000 miles

how do I change the cam shaft position sensor;
check engine light is on and a check of computer board blames the sensor
Avatar
Topsoil
May 20, 2009.



CRANKSHAFT POSITION SENSOR

Removal & Installation (3.8L

1.Disconnect negative battery cable. Remove serpentine belt from crankshaft pulley. Raise vehicle on hoist. Remove right front tire and wheel assembly. Remove right inner fender access cover.

2.Using 28-mm socket, remove crankshaft harmonic balancer bolt. Using Balancer Remover (J-38197), remove harmonic balancer. Remove crankshaft position sensor shield (DO NOT use pry bar). See Fig. 2. Disconnect crankshaft position sensor harness connector. Remove crankshaft position sensor from engine block.

3.To install, reverse removal procedure. Apply Thread Sealer (GM 1052080) to threads of harmonic balancer bolt. Tighten sensor and harmonic balancer bolts to specification.

Fig. 2: Removing Crankshaft Position Sensor Shield


http://www.2carpros.com/forum/automotive_pictures/55316_3800cmps_1.jpg



***Before you perform this, can you post the code number for the MIL?***

Tiny
Zackman
May 20, 2009.
What is a MIL? Also, the engine is a 3.1L not a 3.8L, does that matter?

Tiny
Topsoil
May 21, 2009.
MIL: Malfunction Indicator Light = CEL: Check Engine Light.

Difference in engine makes a big different in camshaft sensor location. In your case, the sensor is under the intake plenum.


http://www.2carpros.com/forum/automotive_pictures/55316_00grandprixcamshaft_1.jpg


Tiny
Zackman
May 22, 2009.
MIL is P0341

Tiny
Topsoil
May 22, 2009.
This has to do with the camshaft sensor circuit, not necessarily the sensor itself. Here is the diagnostic. Unfortunately, a scan tool is necessary to properly perform the diagnostic.

Diagnostic Procedures
1. Perform On-Board Diagnostic (OBD) system check. After performing OBD system check, go to next step.
2. Operate vehicle within FAIL RECORDS data. Using scan tool, monitor SPECIFIC DTC info for this DTC until DTC test runs. If scan tool indicates that this DTC failed this ignition, go to next step. If scan tool does not indicate that this DTC failed this ignition, see DIAGNOSTIC AIDS.
3. Start engine. Using scan tool, observe CAM signal. If scan tool indicates that CAM signal is present, see DIAGNOSTIC AIDS. If scan tool does not indicate that CAM signal is present, go to next step.
4. Turn ignition off. Disconnect CMP sensor harness connector. Turn ignition on, with engine off. Using a DVOM, check voltage between ground and CMP sensor feed circuit. If battery voltage is present, go to step 6. If battery voltage is not present, go to next step.
5. Turn ignition off. Disconnect PCM harness connector. Check CMP sensor feed circuit for short to ground or open circuit. Repair as necessary. After repairs, go to step 16. If circuit is okay, go to step 12.
6. Using a test light connected to battery voltage. Probe test light to CMP sensor ground circuit. If test light illuminates, go to step 8. If test light does not illuminate, go to next step.
7. Turn ignition off. Disconnect PCM harness connector. Check CMP sensor ground circuit for open in circuit. Repair as necessary. After repairs, go to step 16. If circuit is okay, go to step 12.
8. Start engine. Using scan tool, monitor CAM signal. Using a fused jumper wire connected to battery voltage, momentarily touch the signal circuit 5 times for about one second each time. If CAM signal changes each time the signal circuit is touched, go to step 14. If CAM signal does not change each time the signal circuit is touched, go to next step.
9. Check if fuse in jumper wire. If fuse is open, go to step 11. If fuse is okay, go to next step.
10. Check CMP sensor signal circuit for short to voltage or open circuit. Repair as necessary. After repairs, go to step 16. If circuit is okay, go to step 12.
11. Check CMP sensor signal circuit for short to ground. Repair as necessary. After repairs, go to step 16. If circuit is okay, go to next step.
12. Check for poor connections at PCM. Repair as necessary. After repairs, go to step 16. If connections are okay, go to next step.
13. Replace PCM. Program replacement PCM using required equipment. After replacing PCM, go to next step.
14. Check for poor connections at CMP sensor. Repair as necessary. After repairs, go to step 16. If connections are okay, go to next step.
15. Replace CMP sensor. After replacing sensor, go to next step.
16. Using scan tool, read and record FAILURE RECORDS data for this DTC. Operate vehicle within conditions noted in FAILURE RECORDS data. Read SPECIFIC DTC. If scan tool indicates that this DTC FAILED THIS IGN, return to step 2. If scan tool does not indicate that this DTC FAILED THIS IGN, system is okay.

Diagnostic Aid
Check for incorrect harness routing near secondary ignition components, ignition coil arcing to wiring harness or ICM. Check ignition coils for cracks, carbon tracking or other signs of damage. Check for secondary ignition wire(s) arcing to wiring harness.
Check for faulty connections or damaged harness. Observe a voltmeter connected to CMP sensor signal circuit at PCM harness connector while moving all related harness and connectors. A change in voltage indicates fault location.

Tiny
Zackman
May 23, 2009.
2000 Grand Prix GT 3.8 non-supercharged engine was randomly stalling when at operating temperature, at any speed, at any rpm, or idling. Ran well when it ran, but RPMs would randomly drop to zero and the engine would stall. Worsening occaisional no-start condition with no spark. All power in the vehicle remained on. Sometimes would start right back up and other times would not start for 3-30 mins.
No check engine light and so no codes to pull. No traction light issues which sometimes occur when the crankshaft position sensor is failing. I didn't want to change the crankshaft position sensor because, quite frankly, it sucks. Changed the ignition control module. No change. Changed plugs and wires with no change. Finally decided to change the CPS. After much research and finding conflicting information I compiled a procedure with just the truthful parts I found and it worked beautifully and the car runs perfectly now. The CPS on these cars fail. If you have decided to change yours out it is a $35 part and is DIY with the proper information, which follows, some ingenuity, and some mechanical apptitude: Jack and secure car. Remove passenger side tire and the plastic wheel well. The clips will probably break, so buy new ones at a hardware store later. Number and remove spark plug wires from the ignition control module so the car won't start. Remove the center bolt (15/16th inch head) from the harmonic balancer. Easiest way to do this without a doubt is to postion a flat wrench on the bolt, rest the boxed end of the wrench on the car frame in front of the harmonic balancer, and tap the starter. Remember to disable the car from starting. Bolt will break loose. To pull off the harmonic balancer use a standard harmonic balancer puller, but you will need special grade 8 bolts and washers. 1/4-28 bolts, 3" long, one inch of thread is o.K. Place a short 3/8" extension in the crank bolt hole to protect the threads. Carefully, by hand, thread the specialty bolts through the puller and into the 3 holes on the balancer that seemingly have no threads. The threads are farther in and not visible. Make sure the bolts are straight, and inserted to an even depth into the harmonic balancer. Use washers or the bolt heads will gouge and pull through the puller. I turned my specialty bolts 15 quarter turns into the harmonic balancer. Turn the puller's main bolt that it is pushing on the 3/8"extension you placed in the crank bolt's hole. Balancer came right out/off. Remove crankshaft position sensor shield. Mine was plastic. Spread the teeth that connect the shield to its bolts with a small standard screwdriver and pull/pry just a bit. No reason to remove the shield from the bolt farthest towards the rear of the car. You'll be using thread glue on the main bolt when you put in in so you can use some of that on the shield where it connects if you mess up the plastic teeth on the shield a bit. Remove the old sensor's two bolts, and save the part to torture in fire later. Bolt in new sensor, replace shield. Line up the harmonic balancer with its cotter key deal and start pulling the balancer back on with a torque wrench. To keep the engine from turning open the smalll access hole to the flywheel on the bottom of the car (two bolts). Place vicegrips on the flywheel or wedge something in the teeth. Tighten your glued main bolt to 112 lbs plus 76 degrees. You now have a car you can count on and need not worry about it dying while driving down the road. I love mine now. Just wish someone would have made these all inclusive and accurate directions for me.

Tiny
Sylvester2000
Apr 12, 2012.
Any more help needed?

Merlin2021
Apr 12, 2012.