A/T - No Scan Tool Communication With NAG1 Module
NUMBER: 08-046-05GROUP: Electrical
DATE: August 23, 2005
SUBJECT:
Generic Scan Tool - No Communication With NAG1 (W5A580) Transmission Module
OVERVIEW:
This bulletin involves removal of an electrical wire (communication line) from the NAG1 (W5A580) EGS52 transmission control module jumper harness.
MODELS:
2005 (WK) Grand Cherokee
NOTE:
This bulletin applies to WK vehicles equipped with a 3.7L engine and a NAG1 transmission (sales codes EKG and DGJ respectively), and built prior to February 24, 2005 (MDH 0224XX).
SYMPTOM/CONDITION:
A technician, using a Generic Scan Tool (not StarSCAN), may fail to communicate with the vehicle NAG1 transmission control module (TCM). This condition will occur only when certain (aftermarket) Generic Scan Tools are used to attempt communication with the TCM. This condition will NOT occur if the technician uses a StarSCAN scan tool.
DIAGNOSIS:
If the technician experiences the above condition perform the Repair Procedure.
PARTS REQUIRED:
REPAIR PROCEDURE:
1. Turn the ignition switch to the "OFF" position.
2. Remove and isolate the battery negative cable from the battery.
3. Remove the driver side steering column opening cover (knee blocker) from the instrument panel (IP) (Fig. 1). The cover snaps in place at the top and pivots at the bottom of the blocker. The cover has a hand hold just below the steering column. Pull down on the hand hold to unsnap the cover from the instrument panel.
4. The driver side plastic hush panel is located above the brake pedal. Remove the two screws used to secure the driver side hush panel to the instrument panel and removed remove the hush panel.
5. Locate the NAG1 transmission control module (TCM) jumper harness connector (Fig. 1). The connector is a 20-way white color connector. The TCM jumper harness connector is attached to the left side of the brake pedal bracket by a plastic clip.
Remove the connector from the brake pedal bracket carefully prying the clip from the pedal bracket.
6. Depress the connector tab and separate the jumper harness connector.
7. The TCM jumper harness is attached to the IP harness with two harness clips. Remove the harness clips from the IP harness. Route the free TCM jumper harness and connector end into the driver compartment (Fig. 2). This will allow for easy repair to the jumper harness connector.
8. Locate the # 1 cavity in the 20-way jumper harness connector. The # 1 cavity will be occupied by a white with violet trace wire (Fig. 2).
9. Cut the # 1 cavity white w/violet trace wire. Make the wire cut close to the jumper harness connector.
10. Tape back the end of the white w/violet trace wire to the jumper harness. Verify that the end of white w/violet trace wire is fully insulated by tape. Use sufficient electrical tape to insure that the wire end is protected from the metal brake pedal bracket.
11. Route the transmission jumper harness back to its original position.
12. Clip the two (2) harness clips to the IP harness.
13. Connect the ends of the 20-way jumper harness connector together.
14. Make sure the connector attaching clip is properly attached to the 20-way jumper harness connector.
15. Clip the 20-way transmission jumper harness to the brake pedal bracket.
16. Verify that the transmission jumper harness is properly routed (no chafing) and that the 20-way jumper harness connector is secured correctly to the brake pedal bracket.
17. Make sure the driver side hush panel is connected properly at the cowl. Install the hush panel and two screws to the instrument panel.
18. Install the steering column opening cover to the instrument panel.
19. Connect the negative battery cable terminal to the battery. Set the clock to the correct time.
POLICY:
Reimbursable within the provisions of the warranty.
TIME ALLOWANCE:
FAILURE CODE:
Disclaimer:
This bulletin is supplied as technical information only and is not an authorization for repair.