ECM - MIL ON/Poor Driveability

Classification:
HA97-015

Reference:
NTB97-093

Date:
January 1, 1998

1995-97 MAXIMA, MIL "ON" OR POOR DRIVEABILITY DUE TO A/C EVAPORATOR CONDENSATION LEAKING ON ECM

APPLIED VEHICLES:
All 1995-97 Maxima (A32)

SERVICE INFORMATION

If a 1995-97 Maxima exhibits a MIL "ON" and/or poor driveability such as engine hesitation or no starting, the cause may be A/C evaporator condensation leaking onto the engine control module (ECM). A/C condensation can accumulate and leak onto the ECM if the A/C evaporator drain tube becomes blocked by debris such as leaves, insect nests, etc. Such debris can enter the A/C air intake duct through openings in the cowl top cover and around the windshield wiper pivot shafts.

To prevent debris from entering the A/C system, a new cowl top cover and wiper pivot shaft seals are now available. The new cowl top cover has foam seals (mounted on its underside) that keep debris away from the A/C air intake duct. The new wiper pivot shaft seals have additional material ("flaps") that prevent debris from entering the cowl top cover openings around the wiper pivot shafts.

SERVICE PROCEDURE





1. Check for wetness and/or mildew on the passenger side carpeting around the ECM area and check the ECM for signs of water damage (see Figure 1 for ECM location).

A. If the carpeting is dry and mildew-free around the area of the ECM and there are no signs of water damage (wetness, water spots, corrosion, etc.) to the ECM, use the service manual to diagnose the incident DTCs.

B. If the carpeting is wet and/or mildew is present around the ECM and the ECM has signs of water damage (wetness, water spots, corrosion, etc.), proceed with step 2.

3. Discharge the A/C system using the procedure on pages HA-125 and HA-126 of the 1997 Maxima Service Manual.

4. Remove the A/C evaporator assembly.

CAUTION:
Immediately after removing the evaporator assembly, seal the open ends of the refrigerant lines (both on the evaporator and the vehicle) to prevent moisture from entering the A/C system.

5. Using a wet/dry vacuum cleaner, remove all debris inside the evaporator including any debris that may be blocking the drain tube. Make sure the drain tube is free and clear of any debris.

6. Using a wet/dry vacuum cleaner remove all debris inside the intake blower unit. Remove the intake blower unit if necessary.

7. Dry the carpeting using the following steps.

A. With a large towel, soak up as much water as possible from the top surface of the carpet.

B. Pull back the wet sections of the carpet until the underside of the wet section is exposed.

C. Using a wet/dry vacuum cleaner, remove as much water as possible from the underside of the carpet.

D. Spray the wet areas of the carpet with a household disinfectant to eliminate mold or mildew odors and prevent further growth.

E. Allow the carpet to dry.

NOTE:
Use a fan to shorten the drying time.

8. Install the new cowl top cover as follows.

A. Remove the windshield wiper arms (two M10 nuts).





B. Remove and discard the cowl top cover. Save four securing clips (see Figure 2).

C. Using a wet/dry vacuum cleaner, remove all debris in the cowl and A/C intake areas.

D. Install the new cowl top cover.

9. Install the new wiper pivot shaft seals as follows:

A. Remove and discard the old wiper pivot shaft seals.





B. Clean the wiper pivot shafts and apply a light coat of white lithium grease to the sealing surface of the shafts (see Figure 3).

IMPORTANT:
Do not get grease on the tapered surface of the wiper pivot shafts. The tapered surface of the shafts must be clean and free of grease to allow the shafts to properly grip the mating windshield wiper arms.





C. Install the new wiper pivot shaft seals and tuck the "flaps" of the seals under the cowl top cover (see Figure 4).

10. Reinstall the windshield wiper arms and the attachment nuts.

IMPORTANT:
When installing the wiper arms, use the procedure on page EL-112 of the 1997 Maxima Service Manual to properly position the wiper arms. Once correctly positioned, tighten the wiper arm mounting nuts to 21-26 N.m (2.1-2.7 kg-m,15 - 20 ft-lb).

11. Reinstall the A/C evaporator assembly.

NOTE:
When installing the evaporator assembly, make sure the drain tube is correctly positioned and the carpeting does not get caught between the drain tube foam seal and the engine room wall.

12. Evacuate and recharge the A/C system with 0.60-0.70 kg (1.32-1.54 lb) of HFC-134a.

13. Conduct a leak check to confirm there are no refrigerant leaks. Refer to the leak check procedure on pages HA-130 and HA-131 of the 1997 Maxima Service Manual.





PARTS INFORMATION

CLAIMS INFORMATION

When applicable, standard claims coding applies.