Affected Vehicles: All 1996-’97 Nissan trucks

Use this bulletin if a 1996-’97 truck will not maintain idle or idles roughly after an engine cold soak and/or the MIL is on with DTC P0400 stored in the ECM. A countermeasure EGR valve is available to resolve such incidents if the cause is a sticking EGR valve.

Service Procedure
With the engine cold, perform an inspection of the EGR valve as follows:

1. Apply vacuum to the EGR valve with a hand vacuum pump, then release the vacuum (see Figure 1).

2. Check that the EGR valve opens when the vacuum is applied and closes when the vacuum is released.

a. If the EGR valve sticks open or does not open and close smoothly, replace the EGR valve with the countermeasure EGR valve and gasket.

b. If the EGR valve opens and closes smoothly, refer to Trouble Diagnosis in the EC section of the appropriate service manual to diagnose this incident.

Technical service bulletin courtesy of ALLDATA.

For additional information, visit www.alldata.com.