Engine Controls - MIL ON/Multiple Driveability Concerns
No: 01-001/03Last Issued: 01/07/2003
Subject
CAMSHAFT POSITION CMP SYNCHRONIZER TOOL USE DTC P1336 P1309 P0340
APPLICABLE MODEL(S)/VINS
1996-2000 Truck B4000 (OHV engines only)
1995-2003 Truck B3000
DESCRIPTION
An incorrectly installed Camshaft Position Sensor (CMP) synchronizer may be difficult to diagnose. The CMP identifies the # 1 cylinder compression stroke to the PCM. It is important to install a gear driven Camshaft Position (CMP) Sensor synchronizer correctly.
If a sensor is installed incorrectly, it may exhibit poor fuel economy, drive ability concerns (loss of power, surge, hesitation, rolling idle, runs rough), the MIL may come on with DTCs (P1336, P1309, P0340).
Incorrect installation includes:
- Engine was not set to TDC # 1 cylinder before CMP sensor synchronizer installation
- The incorrect CMP synchronizer installation tool was used
- Incorrect alignment of the CMP synchronizer tool
- The CMP synchronizer was turned after installation
This bulletin describes how to diagnose an incorrectly installed CMP sensor synchronizer using WDS and proper procedure and tools for installing a CMP sensor synchronizer.
CMP SENSOR TYPES
There are two types of CMP sensors:
1. Hall Effect CMP Sensor
- 3-pins
- Uses differential voltage across windings to generate a signal
- Waveform appears similar to a sine wave
2. Variable Reluctance CMP Sensor
- 2-pins
- Uses a magnet and Hall Effect device to generate a signal
- Waveform appears as a square wave
DIAGNOSIS USING WDS
NOTE:
Before performing this diagnosis, inspect service history to determine if it is possible that a repair was performed that could lead to incorrect CMP synchronizer installation.
1. Run WDS Power Balance test to inspect for possible misfire:
- If misfire is present, perform Workshop Manual diagnosis to correct the cause of misfire.
- If misfire is no present go to step 2.
2. Turn ignition OFF
3. Disconnect number one cylinder Fuel Injector electrical connector (passenger side front).
4. Start the engine.
5. Perform WDS Power Balance Test.
6. The Power Balance Test should indicate power loss on the # 1 cylinder:
- If power loss is indicated in the # 1 cylinder, the CMP synchronizer is installed correctly, go to step 7.
- If any cylinder other than # 1 is indicated, then the CMP synchronizer assembly is installed incorrectly and must be reinstalled. Perform the CMP SENSOR SYNCHRONIZER INSTALLATION PROCEDURE,
7. Connect the # 1 cylinder injector electrical connector.
8. Connect the 104 Pin Breakout Box (49UN-01-1300) between the PCM and the PCM electrical connector.
9. Connect the WDS probes to the Breakout Box:
Red WDS probe to Breakout box pin # 21.
- Black WDS probe to Breakout box pin # 85.
10. Select Oscilloscope from the WDS Toolbox.
A. Select "Channel one Auto Mode".
- Select CKP sensor.
B. Select "Channel two Auto Mode"
- Select the correct CMP sensor:
^ 2-wire sensors are VRS
^ 3-wire sensors are Hall Effect
C. Press the Start button.
D. Monitor and compare the CMP and CKP sensor waveforms:
E. CMP Sensor Waveforms:
^ 2-wire VRS
Verify that the falling edge of the CMP waveform should cross the zero reference line between the 7th and 10th peak past the missing tooth of the CKP sensor.
- The CKP sensor waveform has a missing tooth which appears as an extra space between the waveforms. This position is 60 degrees BTDC
- If the falling edge falls between the 7th and 10th peak compared to the CKP, then the CMP is installed correctly and is not the source of your symptom, proceed with Normal DTC or Symptom troubleshooting in the Workshop Manual.
- If the falling edge does not fall between the 7th and 10th peak compared to the CKP, the CMP synchronizer is not installed correctly, perform the CMP SENSOR SYNCHRONIZER INSTALLATION PROCEDURE.
^ 3-wire Hall Effect
The rising edge of the CMP timing waveform should occur between the 7th and 10th peak past the missing CKP tooth.
- The CKP sensor waveform has a missing tooth which appears as an extra space between the waveforms. This position is 60 degrees BTDC
- If the rising edge falls between the 7th and 10th peak compared to the CKP, then the CMP is installed correctly and is not the source of your symptom, proceed with Normal DTC or Symptom troubleshooting in the Workshop Manual.
- If the rising edge does not fall between the 7th and 10th peak compared to the CKP, the CMP synchronizer is not installed correctly, perform the CMP SENSOR SYNCHRONIZER INSTALLATION PROCEDURE.
CMP SENSOR SYNCHRONIZER INSTALLATION PROCEDURE
1. Set # 1 cylinder to TDC of compression stroke.
NOTE:
This is the most critical step of the procedure, it is important to correctly set # 1 to TDC of compression, or the synchronizer will be incorrectly installed.
2. Record customer radio station pre-sets.
3. Disconnect battery ground cable.
4. Remove the CMP sensor from the synchronizer assembly.
5. Remove synchronizer clamp bolt and the synchronizer assembly.
NOTE:
The oil pump intermediate shaft may not come out with the synchronizer assembly, if it does not, retrieve it.
6. Obtain the correct Engine Synchro Positioning Tool:
- 3.0L 1995-1997 (3-wire CMP sensor) use 303-529 or49-UN01-148
- 3.0L 1998-2003 (2-wire CMP sensor) use 303-589 (303-638 cannot be used, the handle will not clear the intake manifold)
- 4.0L 1996-mid 1998 (3-wire CMP sensor) use 30-529 or 49-UN01-148
- 4.0L mid 1998-2000 (2-wire CMP sensor) use 303-638 or 303-589
7. Coat the synchronizer drive gear with clean engine oil.
8. Install the Engine Synchro Positioning Tool to the synchronizer assembly:
a. Rotate the tool until it engages the notches in the camshaft synchronizer housing and the armature
b. The arrow on the tool will rotate during installation until the intermediate shaft and camshaft gear fully engage
c. While installing the camshaft synchronizer, make sure the arrow points to the correct position:
- 3.0L (1995) 38 degrees from the engine centerline
- 3.0L (1996-1997) 75 degrees from the engine centerline
- 3.0L (1998-2003) 38 degrees from the engine centerline
- 4.0L (1995-1997) 60 degrees from the engine centerline
- 4.0L (1998) 54 degrees from the engine centerline
- 4.0L (1999 to mid 2000) 15 degrees from the engine centerline
NOTE:
This step is critical for alignment of the CMP electrical connector, it does not affect timing. However, you must use this tool and procedure1 if you attempt to rotate the CMP to connect the CMP electrical connector after synchronizer installation, timing will be affected. The only way to adjust the synchronizer assembly position is to time the engine to # 1 TDC compression and use the Engine Synchro Positioning Tool.
9. Install the synchronizer clamp bolt.
- Torque the bolt to 25 Nm (18 lb-ft)
10. Remove the Engine Synchro Positioning Tool.
11. Install the CMP sensor.
- Torque the CMP bolts to 3 Nm (27 Lb-in)
12. Connect the battery ground cable.
13. Reset customers radio station pre-sets.
14. Verify repair.
WARRANTY INFORMATION
Note:
The process of setting the correct CMP position is a normal part of servicing the CMP sensor and is included in the labor operation for that individual repair.
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