Engine Controls - Spark Knock, Especially at High Temps

BULLETIN NUMBER:
NTB97-058

CLASSIFICATION:
EC97-027

DATE:
August 13,1997

TITLE:
SPARK KNOCK

MODELS:
1995-97 MAXIMA

This bulletin supersedes NTB96-068/EC96-009. This bulletin expands the range of Applied Vehicles and updates the Parts Information. Please discard NTB96-068/EC96-009.

APPLIED VEHICLE(S):
1995-97 Maxima (A32)

APPLIED VIN(S):
Vehicles build before JNKCA21D8VT512147, JN1CA21D8VT833870, JN1CA21D1VT215614 and JN1CA21*VT510709

APPLIED DATE(S):
Vehicles built before December 10, 1996

SERVICE INFORMATION

Follow the procedure contained in this bulletin to diagnose and repair 1995-97 Maxima vehicles if spark knock is heard especially when operating in high ambient temperature/low humidity conditions. A countermeasure engine control module (ECM) is available to resolve this incident.

SERVICE PROCEDURE

1. Make sure the customer is using premium unleaded gasoline. If not, inform the customer that using premium gasoline will reduce the level of spark knock. Recommend that the customer begin using it and return the vehicle.

2. Use CONSULT to check Self Diagnosis Results. Use the service manual to repair any codes you find.

3. Confirm that the exhaust gas recirculation (EGR) system is operating normally as follows:

A. Connect CONSULT and drive the vehicle.

B. Use the CONSULT-'Data Monitor' mode to monitor the EGR temperature sensor (EGR Temp Sen) voltage and EGR control solenoid valve (EGRC SOL/V) during EGR operating conditions.

1) When the EGR system is operating (EGR gas flowing), the EGRC SOL/V will be OFF and the EGR Temp Sen voltage should decrease to below 1.0 volts.

2) The EGR system is not operating when the EGRC SOL/V is ON and the EGR Temp Sen voltage increases to above 1.0 volt.

IMPORTANT: The EGR system operates under cruise and light acceleration. The EGR system does not operate when the throttle is closed or under heavy acceleration.

If the EGR system is not operating correctly, use the service manual to troubleshoot the system.





4. If the customer is using premium unleaded gasoline and the EGR system is operating normally, replace the ECM (see Figure 1) with the appropriate countermeasure part listed in the Parts Information table.

Before replacing the ECM, see steps 1 through 4 of the PRECAUTIONS AND PREPARATION section, page EC-5 of the service manual.





PARTS INFORMATION

CLAIMS INFORMATION

If applicable, normal claims coding applies.