DTC 71

CIRCUIT DESCRIPTION
The EGR system recirculates exhaust gas, which is controlled to the proper quantity to suit the driving conditions, into the intake air mixture to slow down combustion, reduce the combustion temperature and reduce NOx emissions.
The lift amount of the EGR valve is controlled by a step motor operated by the ECM. The ECM operates the motor only a preprogrammed amount in response to the engine operating conditions (engine speed, intake air volume to adjust the EGR volume to the target valve.)
Under the following conditions, EGR is cut to maintain driveability.
- Engine coolant temp. below 53°C (127.4°F)
- During deceleration (throttle valve closed).
- Light engine load (amount of intake air very small).
- Engine speed over 4,000 rpm.
- Engine idling.








DETECTING CONDITION AND TROUBLE AREA

NOTE: (*) This indicates items for which "2 trip detection logic" is used. With this logic, when a logic malfunction is first detected, the malfunction is temporarily stored in the ECM memory. If the same case is detected again during the second drive test, this second detection causes the malfunction indicator lamp to light up.
The 2 trip repeats the same mode a 2nd time. (However, the IG switch must be turned OFF between the 1st trip and 2nd trip).
In the Test Mode, the malfunction indicator lamp lights up the 1st trip a malfunction is detected.

DIAGNOSIS TROUBLE CODE DETECTION DRIVING PATTERN
Purpose of the driving pattern:
- To simulate diagnostic trouble code detecting condition after diagnostic trouble code is recorded.
- To check that the malfunction is corrected when the repair is completed confirming that diagnostic trouble code is no longer detected.

Malfunction: Open in EGR gas temp. sensor circuit.





1. Disconnect the EFI fuse (30 A) for 10 sec. or more, with IG switched OFF. Initiate test mode (Connect terminals TE2 and E1 of data link connector 2 with IG switched OFF).
2. Start the engine and warm up.
3. Let the engine idle for 3 minutes.
4. With the A/C ON and transmission in D position (O/D OFF), drive at 88 - 96 km/h (55 - 60 mph) for 4 min. or less.

HINT: If a malfunction exists, the malfunction indicator lamp will light up during step 4.

NOTICE: If the conditions in this test are not strictly followed, detection of the malfunction will not be possible.





DIAGNOSTIC CHART





WIRING DIAGRAM























INSPECTION PROCEDURE