DTC P0401 Exhaust Gas Recirculation Flow Insufficient Detected

Transcription

1 DI84 DIAGNOSTICS IN DI01510 DTC P0401 xhaust Gas Recirculation Flow Insufficient Detected CIRCUIT DSCRIPTION The GR 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 amount of GR is regulated by the GR vacuum modulator according to the engine load. If even one of the following conditions is fulfilled, the VSV is Throttle Valve Intake Chamber Throttle Body GR Valve VSV xhaust Gas CM GR Vacuum Modulator P25430 turned ON by a signal from the CM. This results in atmospheric air acting on the GR valve, closing the GR valve and shutting off the exhaust gas (GR cutoff). Under the following conditions, GR is cut to maintain driveability. Before the engine is warmed up. During deceleration (throttle valve closed). Light engine load (amount of intake air very small). ngine idling. ngine speed over 4,400 rpm. High engine load (amount of intake air very large). DTC No. DTC Detecting Condition Trouble Area P0401 After the engine is warmed up, intake manifold absolute pressure is larger than value calculated by CM while GR system is ON (2 trip detection logic) Vacuum or GR hose disconnected Open or short in VSV circuit for GR VSV for GR GR system GR vacuum modulator GR valve stuck closed Manifold absolute pressure sensor CM 281

2 DIAGNOSTICS IN DI85 WIRI DIAGRAM V8 VSV for GR B R B W GR CM 11 IG1 01 From Battery From IG Switch R W B W 7 1I 3 1A FI Relay B R 1C W B 1D Instrument Panel J/B ID A13158 SYSTM CHCK DRIVI PATTRN Vehicle Speed km/h (38 50 mph) (3) (5) Idling IG SW OFF (1) (2) (4) S06906 Warm up 3 5 min. 3 min. 3 5 min. 2 min. Time A10765 (1) Connect the OBD II scan tool or TOYOTA handheld tester to the DLC3. (2) Start and warm up the engine with all the accessories switched OFF. (3) Run the vehicle at km/h (38 50 mph) for 3 min. or more. (4) Idle the engine for about 2 min. (5) Do steps (3) and (4) again. (6) Stop at safe place and turn the ignition switch OFF. (7) Do steps (2) to (5) again. (8) Check the RADINSS TSTS mode on the OBD II scan tool or TOYOTA handheld tester. If COMPL is displayed and the MIL does not light up, the system is normal. If INCMPL is displayed and the MIL does not light up, run the vehicle steps (2) to (6) for some times and check it. 282

3 DI86 DIAGNOSTICS IN HINT: INCMPL is displayed when either condition (a) or (b) exists. (a) The system check is incomplete. (b) There is a malfunction in the system. If there is a malfunction in the system, the MIL will light up after step (7) above is done. (2 trip detection logic) INSPCTION PROCDUR HINT: If DTCs P0105, P0106 and P0401 are output simultaneously, perform troubleshooting of DTC P0105 first. If DTCs P0401 and P0402 are output simultaneously, perform troubleshooting of DTC P0402 first. Read freeze frame data using TOYOTA handheld tester or OBD II scan tool. Because freeze frame records the engine conditions when the malfunction is detected. When troubleshooting, it is useful for determining whether the vehicle was running or stopped, the engine was warmed up or not, the airfuel ratio was lean or rich, etc. at the time of the malfunction. TOYOTA handheld tester: 1 Check connection of vacuum hose and GR hose (See page C10 ). 2 Check VSV for GR. Filter System: OFF G System: ON A00407 PRPARATION: (a) Connect the TOYOTA handheld tester to the DLC3. (b) Turn the ignition switch ON and push the TOYOTA handheld tester main switch ON. (c) Select the ACTIV TST mode on the TOYOTA handheld tester. CHCK: Check the operation of the VSV when it is operated by the TOY OTA handheld tester. : GR system is OFF: from port flows out through the air filter. GR system is ON: from port flows out through port G. Go to step

4 DIAGNOSTICS IN DI87 3 Check operation of VSV for GR (See page SF45 ). Replace VSV for GR. Check for open and short in harness and connector between J/B No.1 and CM (See page IN33 ). 4 Check GR system (See page C10 ). 5 Check GR vacuum modulator (See page C10 ). 6 Check GR valve (See page C10 ). 7 Check manifold absolute pressure sensor (See page SF55 ). 284

5 DI88 DIAGNOSTICS IN Check and replace CM (See page IN33 ). OBD II scan tool (excluding TOYOTA handheld tester): 1 Check connection of vacuum hose and GR hose (See page C2 ). 2 Check VSV for GR. GR ON Filter VSV is ON 4 Connector ON OFF G VSV is OFF A00408 PRPARATION: (a) Remove the floor carpet center cover (See page SF63 ). (b) Disconnect the 4 connector from the CM. (c) Turn the ignition switch ON. CHCK: Check the VSV function. (1) Connect between terminal GR of the CM connector and body ground (ON). (2) Disconnect between terminal GR of the CM connector and body ground (ON). : (1) VSV is ON: from port flows out through the air filter. (2) VSV is OFF: from port flows out through port G. Go to step 4. 3 Check operation of VSV for GR (See page SF45 ). Replace VSV for GR. 285

6 DIAGNOSTICS IN DI89 Check for open and short in harness and connector between J/B No.1 and CM (See page IN33 ). 4 Check GR system (See page C10 ). 5 Check GR vacuum modulator (See page C10 ). 6 Check GR valve (See page C10 ). 7 Check manifold absolute pressure sensor (See page SF55 ). Repair and replace. Check and replace CM (See page IN33 ). 286