DTC 71

Diag. Trouble Code 71 EGR System Malfunction (Only for USA spec.)

CIRCUIT DESCRIPTION






The EGR system is designed to recirculate the exhaust gas properly controlled according to the driving condition back into the intake air-fuel mixture. It helps to slow down combustion in the cylinder and thus lower the combustion temperature which, in turn, reduces the amount of NOx emission. The amount of FGR is regulated by the EGR vacuum modulator according to the engine load.

If even one of the following conditions is fulfilled, the VSV is turned ON by a signal from the ECM. This results in atmospheric air acting on the EGR valve, closing the EGR valve and shutting off the exhaust gas (EGR cut-OFF).

Engine coolant temp. below 50° C (122° F)
During deceleration (throttle valve closed)
Light engine load (amount of intake air very small).
Engine speed over 5,200 rpm.
Traction control is operating.






DIAGNOSIS TROUBLE CODE DETECTION DRIVING PATTERN

Purpose of the driving pattern.

(a) To simulate diag. trouble code detecting condition after diag. trouble code is recorded.

(b) To check that the malfunction is corrected when the repair is completed confirming that diag. trouble code is no longer detected.






1.Disconnect the EFI fuse (15 A) for 10 sec. or more, with IG switch OFF. Initiate test mode (Connect terminal TE2 and El of DLC1 or DLC2 with IG switch OFF).
2. 02 Start the engine and warm up.
3. After the engine is warmed up, let it idle for 3 min.
4. With the A/C ON and transmission in 5th gear (Electronic Controlled Transmission in 3rd speed) drive at 55 60 mph (88 96 km/h) for 4 mm or less.

HINT: If a malfunction exists, the malfunction indicator lamp will light up during step 04

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

Diagnostic chart






Wiring diagram






INSPECTION PROCEDURE