Issue Summary:

• On 1996 and newer Dodge and Jeep vehicles, deteriorated PCM connectors can cause a variety of diagnostic trouble codes.
• Ford Escort/Mercury Tracer sedans have experienced a condition in which the transmission operates properly until the headlights are turned on, at which time the transmission is stuck in third gear and remains there until the headlights are turned off.
• At the start of production for the 1996 model year, Nissan redesigned the throttle-position sensor and idle/full-throttle switch assembly.
• Ford Taurus/Mercury Sable cars with the 3.0-liter, 12-valve Vulcan V-6 engine may develop a leak from the engine rear-main oil seal after fly-wheel replacement.

Deteriorated PCM connectors causing a variety of diagnostic trouble codes.

The PCM on 1996 and later vehicles is in the engine compartment (see Figure 1).

This location allows connectors A, B and C (see Figure 2) and their associated wiring plugging into the PCM to be subjected to engine-compartment heat for sustained periods of time. This heat combined with weathering contributes to the deterioration of the connector.

Chrysler/Dodge/Plymouth has made available PCM-connector repair kits under the following part numbers:

• Connector A (32-terminal black C-1 connector) . . . . . .56017957
• Connector B (32-terminal white C-2 connector) . . . . . .56018614
• Connector C (32-terminal gray C-3 connector) . . . . . . .56018615
• 20 wires with terminals on both ends and 40 pieces of heat-shrink tubing . . . . .04882087
• Connector Cover . . . . . . . . . . . . . . . . . . . .56018606
• Connector Plug . . . . . . . . . . . . . . . . . . . . .56038347

1. Record the memorized preset radio stations
2. Disconnect the battery or batteries on vehicles with 5.9-liter Cummins diesel engines and isolate the cable ends.
3. Unplug the damaged connector from the PCM
4. Locate and inspect the connector lock tab and insulator for damage (see Figure 3). If it is damaged, the entire connector will need to be replaced.
5. Write down each wire color and its appropriate cavity location within the connector before disassembling the connector.
6. Next, pull on the wires individually. If they come out, the connector will need to be disassembled to inspect the initial and final locks (see Figure 3).
7. To disassemble the connector, push in on the single locking tab (see Figure 4).
8. Insert Chrysler’s special tool 6934 or one similar into the back of the insulator cavity alongside each wire, removing them from the connector assembly one at a time (see Figure 5).
9. With all the wires removed from the connector, inspect the entire connector assembly (see Figure 3). If any of the parts are damaged, replace the connector assembly.
10. While the wires are out of the connector, inspect each terminal end for damage or corrosion. Place each terminal end onto the mating pin in the PCM and check for drag (see Figure 6). If any of the connections are loose, replace the wire.
11. Using the notations of wire color and location made in step 5, carefully assemble the new and/or repaired connector assembly. When all of the wires are in place, push the two locking tabs into place to secure the wire terminals in the connector assembly (see Figure 7).
12. Cross your fingers, attach the battery cable or cables, reset the radio stations and pray that all your codes do not return.

The transmission operates properly until the headlights are turned on, at which time the transmission is stuck in third gear and remains there until the headlights are turned off. The transmission now returns to proper operation.

In many instances, the license-plate lights will be dim.

The problem is the G401 ground in the right-rear corner of the trunk (see Figure 8). When this ground is bad, feedback goes through the inhibitor-switch reverse-lamp circuit. When the computer receives this signal, it turns off all shift solenoids and the transmission is in third gear, because all shift solenoids are normally commanded off in reverse.

The loss of ground is created by the continual opening and closing of the trunk lid, which is where the license-plate and reverse-lamp assemblies are. The license-plate and reverse-lamp wiring sub-harness travels along the inside of the trunk and up to the passenger-side trunk-lid hinge, where it joins the rest of the vehicle wiring harness, also shown in Figure 8. This is where the constant flexing of the license-plate and reverse-lamp sub-harness takes place, which results in the G401 ground wire breaking and causing the complaint.

Remove the tape from this area of the wiring harness and repair the broken ground wire.

Note:

In the left-rear corner of the trunk, shown in Figure 8, is the G402 ground, which is spliced to the G401 ground. In the event the problem for this complaint is not found at the area of the passenger-side trunk-lid hinge, be sure to check the G402 ground circuit as well.

The throttle-position sensor and idle/full-throttle switch assembly was redesigned at the start of production for the 1996 model year.

• (1) The throttle-position sensor and idle/full-throttle switch assembly.
• (2) The vehicle-harness connectors because of terminal reassignment.

The current-design throttle-position sensor and idle/full-throttle switch assembly will not interchange with the previous design.

TPS part numbers will vary with engine and model application for both front- and rear-wheel-drive vehicles.

After flywheel replacement, the vehicle may return with a leak from the engine rear-main oil seal. The vehicle did not have this leak after the road-test leak check.

On Ford Taurus and Sable cars equipped with the 3.0-liter, 12-valve Vulcan V-6 engine, over-tightening the flywheel-to-crankshaft bolts can easily pull the crankshaft out of round, causing the seal to leak.

When replacing the fly-wheel, be sure to install it with the stiffener plate toward the transmission, and torque the flywheel-to-crankshaft bolts to 54-64 lb.-ft. in a cross pattern as shown in Figure 11.

July 2003 Issue
Volume 20, No. 7

• 1996 and Newer Dodge and Jeep Vehicles: PCM-Connector Repair Kit
• Ford Escort/Mercury Tracer Sedan: Stuck in Third Gear
• Nissan: Redesigned Throttle-Position Sensor and Idle/Full-Throttle Switch
• Ford Taurus/Mercury Sable With 3.0-Liter Vulcan Engine: Rear-Main Oil-Seal Leak