Inspection Procedure

DTC 71 EGR System Malfunction





WIRING DIAGRAMS

INSPECTION PROCEDURE
1. CHECK VOLTAGE BETWEEN TERMINAL "EGR" OF ENGINE CONTROL MODULE (ECM) CONNECTOR AND BODY GROUND.
(a) Connect the Check Harness A.
(b) Warm up engine to normal operating temperature.



(c) Measure voltage between terminal EGR of ECM connector and body ground.

Voltage: 9 - 14 volts

- If OK proceed to step 4.
- If not OK proceed to step 2.

2. CHECK RESISTANCE ACROSS TERMINALS OF VSV FOR EGR.
(a) Remove VSV for EGR.



(b) Measure resistance between terminals of VSV for EGR.

Resistance: 30 - 40 Ohms at 20°C (68 °F)

- If OK proceed to step 3.
- If not OK replace VSV for EGR.

3. CHECK FOR OPEN AND SHORT IN HARNESS AND CONNECTOR BETWEEN EFI MAIN RELAY AND VSV FOR EGR. CHECK FOR OPEN AND SHORT IN HARNESS AND CONNECTOR BETWEEN VSV FOR EGR AND ECM.
- If OK check and replace ECM.
- If not OK repair or replace harness or connector.

4. CHECK EGR SYSTEM.
- If OK proceed to step 5.
- If not OK repair EGR system.

5. CHECK RESISTANCE OF EGR GAS TEMPERATURE SENSOR.
(a) Remove EGR gas temperature sensor.



(b) Measure resistance between terminals of EGR gas temperature sensor connector.

Resistance:
64 - 97 K-Ohms at 50°C (122°F)
11 - 16 K-Ohms at 100°C (212°F)
2 - 4 K-Ohms at 150°C (302°F)

- If OK proceed to step 6.
- If not OK replace EGR gas temperature sensor.

6. CHECK FOR OPEN IN HARNESS AND CONNECTOR BETWEEN EGR GAS TEMPERATURE SENSOR AND ECM.
- If OK check and replace ECM.
- If not OK repair or replace harness or connector.