Crankshaft Position Sensor - Intermittent No Start

88amcjeep09

Models


1988-89 Premier


Subject


Intermittent NoStart Condition


Index


DRIVEABILITY


Date

October 10, 1988

No.


18-55-88


P-4232 (C08-61)
SYMPTOM/CONDITION


Some 1988-89 Premier vehicles may experience an intermittent nostart condition during engine cranking. This condition may be caused by an inadequate crank position sensor (CPS) signal to the engine control unit (ECU).


DIAGNOSIS


Prior to performing the procedure in this bulletin verify that the vehicle has been checked with the MS 1700 or DRB II Engine Diagnostic Tester and any indicated malfunction corrected.

If a problem persists proceed with the following repair procedure.


PARTS REQUIRED


Patch Harness Kit: PN 4443-965 Crank Position Sensor Patch Harness With Tie Straps (1) Separate Tie Straps (2)

FIGURE 1:

REPAIR PROCEDURE


1. Disconnect the battery negative terminal.

2. From the engine side, inspect the bulkhead area below the heater fan motor and verify that the vacuum (A) and fuel lines (B) are clear of this area before drilling. Figure 1
3. Remove the three (3) nuts which retain the Engine Control Unit (ECU) to the instrument panel.

4. Disconnect the two harness connectors from the ECU and remove the ECU.

FIGURE 2:

5. Locate the round sound insulation retaining clip (E) under the heater-A/C housing. Figure 2
6. Drill a 1/2" diameter hole (F) through the bulkhead 1-1/2" to the right and 3/4" above the sound insulation retaining clip (E) as shown in Figure 2. Remove all metal burrs from around the drilled hole.

7. Disconnect the Crank Position Sensor (CPS) connector at the rear of the left cylinder head from the Engine Control (EEC) harness.

FIGURE 3:

8. Connect the CPS patch harness to the CPS (G). Route the CPS patch harness along the bulkhead and secure it to the existing engine control harness with three tie straps. Figure 3.

FIGURE 1:

9. Insert the CPS patch harness through the 1/2" drilled hole in the bulkhead and fully seat the CPS patch harness grommet (H) in the drilled hole. Figure 1

FIGURE 4:

10. Locate the larger (32-way) of the two ECU harness connectors and note the location and color code of the wires in the C1 and D1 terminal cavities. Remove the two wire locks (K) from the 32-way connector. Figure 4

FIGURE 5:

FIGURE 6:

11. Modify a large paperclip (L) and remove the. white w/black tracer wire from the C1 cavity as shown in Figure 5. Insert the white w/black tracer wire labeled C1 from the CPS patch harness into the C1 Cavity of the 32-way connector. Figure 6

FIGURE 6:

12. Remove the red w/green tracer wire labeled D1 from the D1 cavity and insert the red w/green tracer wire labeled D1 from the from the CPS patch harness into the D1 cavity of the 32-way connector. Figure 6

13. Cut the terminal end off the old D1 and C1 wires to prevent future use. Tape the two cut wires (M) back to the EEC harness. Figure 6

14. Install the two wire locks (K) into their original positions on the 32-way connector. Figure 6

15. Secure the CPS patch harness to the EEC harness with one tie strap (N). Figure 6
16. Install both ECU connectors to the ECU and insure that all wire terminals and both connectors are fully engaged to the ECU.

17. Install the ECU to the instrument panel with the three retaining nuts.

FIGURE 7:

18. Locate the EEC 34-way connector (P) on the engine side of the bulkhead and tighten connector bolt to 71 in.lbs (8 N-m) of torque. Figure 7
19. Connect the battery negative terminal.


POLICY: Reimbursable within the provisions of the warranty.


TIME ALLOWANCE:
Labor Operation No. 08-90-65-90 . . . . . . . . . 0.6 Hrs.


FAILURE CODE: 85 - Improperly Installed Wiring