MIL ON With One or More O2 Sensor DTCs

Reference:
ITB99-003

Classification:
EC98-031

Date:
March 1, 1999

97-99 QX4 MIL "ON" WITH O2 SENSOR DTCs

APPLIED VEHICLE(S): 97-99 QX4 (JR50)
APPLIED DATE: Manufactured prior to 11/17/98

SERVICE INFORMATION

If a 1997-1999 QX4 shows the MIL "ON" and one or more of the following DTCs are stored in ECM:

- 97 vehicle: DTC P0130, P0150, P0136, or P0156

- 98-99 vehicle: DTC P0131, P0134, P0138, P0140, P0151, P0154, P0158, P0160,

use this bulletin to diagnose and repair the incident.

This incident can be caused by poor grounding between the intake manifold and the engine cylinder head. The incident can be verified with a voltage drop check (see below). The incident is corrected by the installation of a sub-harness between the intake manifold ground bolts for the engine harness and the right hand (RH) cylinder head to provide a direct grounding path.

SERVICE PROCEDURE

1. Check for poor grounding using a DVOM to measure the voltage drop between the intake manifold ground bolt for the engine harness and the right hand (RH) cylinder head. At engine warm idle, place the red meter lead on the intake manifold ground bolt for the engine ECCS harness and the black lead on RH cylinder head and measure the voltage.

A. If the voltage is less than 0.020V (20 millivolts), this bulletin does not apply. Use the service manual to diagnose this incident.

Figure 1:

B. If the voltage is above 0.020V (20 millivolts), install the sub-harness shown in Figure 1 for additional grounding. Continue with step two of this bulletin.

Figure 2:

2. Route the sub-harness from the RH cylinder head, on the existing ECCS harness, towards the center front of the engine and then back towards the intake manifold collector (see Figure 2).

Figure 3:

3. Secure the sub-harness end with the two larger eyelet's to the two available threaded holes in the RH head adjacent to the negative battery cable attachment point (see Figure 3). Use the two new hex bolts listed in the parts information.

CAUTION: To prevent damage, the sub-harness must be positioned more than 70 mm (2.8 in.) from the exhaust manifold.

4. Secure the sub-harness to the ECCS harness at four (4) places (see Figure 4) using the wiring clips listed in the parts information. Note the spacing between the wiring clips shown in Figure 4.

Figure 4:

5. Secure the sub-harness end with the two smaller eyelet's to two of the existing ground bolts located on the intake manifold (see Figure 4).

6. Trim the excess material from the newly installed wiring clips.





PARTS INFORMATION

CLAIMS INFORMATION





Submit a Primary Failed Part (PP) line using the claims coding as shown.