P0400

DTC P0400 EXHAUST GAS RECIRCULATION FLOW MALFUNCTION





SYSTEM DIAGRAM






WIRING DIAGRAM






DETECTING CONDITION






DTC CONFIRMATION PROCEDURE

WARNING:
- When performing a road test, select a place where there is no traffic or possibility of a traffic accident and be very careful during testing to avoid occurrence of an accident.
- Road test should be carried out with 2 persons, a driver and a tester, on a level road.

NOTE: Check to make sure that following conditions are satisfied when using this DTC CONFIRMATION PROCEDURE.
- Intake air temp. or intake air temp. at start: higher than -7°C (19°F)
- Engine coolant temp. at start: higher than -7°C (19°F)
- Atmospheric pressure: higher than 570 mmHg (Altitude: lower than 2360 m (7740 ft)






TROUBLESHOOTING


EGR SYSTEM CHECK

Using SUZUKI scan tool.




1) Connect SUZUKI scan tool to DLC with ignition switch OFF.
2) Start engine





3) When engine is cool (coolant temperature is below 55°C, 131°F), race engine and check that EGR valve diaphragm is not operating in this state, by touching diaphragm with finger.

CAUTION: If EGR valve is hot, it may be necessary to wear gloves to avoid burning fingers.





4) Warm up engine to normal operating temperature (coolant temperature is above 80°C (176°F)
5) Turn ON EGR solenoid vacuum valve by using SUZUKI scan tool.

NOTE; Increasing engine speed to higher than 3,000 r/min, driving vehicle or insufficient engine warm-up, will result in interrupting scan tool control.





6) Check to be sure that diaphragm moves toward 1 (in figure) during acceleration and toward 2 during deceleration.
If EGR valve fails to operate properly, check vacuum hoses, EGR valve, EGR pressure transducer, EGR solenoid vacuum valve, EGR solenoid vacuum valve (for system check), wire harness and ECM.
7) Keep engine running at idle speed and open EGR valve by hand, and engine should either stop or reduce its speed. If neither occurs, EGR passage is clogged. Clean it.





Not using SUZUKI scan tool
Different from when using SUZUKI scan tool described previously, it is necessary to input vehicle speed to ECM to cause EGR valve to operate.

When checking operation of EGR valve, hoist vehicle, start engine, release parking brake lever and check that rear propeller shaft (rear wheels) is turning.

If not, perform following check with one rear tire locked and the other turned by hand.

WARNING: Make sure that M/T or A/T is set to "Neutral" position for this check. If it is set to any other position, rear tires will turn at high speed and a very dangerous situation may occur.

Vacuum Hose Inspection
Check hoses for connection, leakage, clog and deterioration.
Replace as necessary.





EGR valve Inspection
1) Disconnect vacuum hose from EGR solenoid vacuum valve (for system check).
2) Connect vacuum pump gauge to its hose.
3) Check that EGR valve diaphragm moves smoothly and that it is held at the same position when 20cm Hg vacuum is applied to EGR valve.
If diaphragm fails to move smoothly, or it isn't held at the same position, replace EGR valve.
4) After checking, be sure to connect vacuum hose.

EGR Pressure Transducer Inspection





1) Check filter for contamination and damage. Using compressed air, clean filter.





2) Remove EGR pressure transducer and plug nozzle with finger.
Blow air into another nozzle and check that air passes through to air filter side freely.





3) Connect vacuum pump gauge to nozzle "P" and plug nozzle "Q" with finger.
While blowing air into nozzle "A", operate vacuum pump gauge and check that vacuum is applied to pressure transducer.
Then stop blowing nozzle "A" and check that vacuum pump gauge indicates "0" (zero).
If check result is not satisfactory, replace EGR pressure transducer.





4) After checking, install pressure transducer and connect hoses securely.

EGR Solenoid Vacuum Valve and Its Circuit Inspection





1) Disconnect vacuum hoses from pipes.
2) Blow into hose "A" with ignition switch ON.
Air should come out of hose "B" and not out of filter.
If not, proceed to step 4).





3) Start engine and run it at idle speed.
In this state, blow hose "A".
Air should come out of filter and not out of hose "B".
If check results are as describe above EGR solenoid vacuum valve and its circuit are in good condition, connect vacuum hoses securely.
If not, proceed to step 4).





4) With ignition switch OFF, disconnect coupler from solenoid vacuum valve.
5) Check resistance between two terminals of solenoid vacuum valve.

Resistance of EGR solenoid vacuum valve:
28 - 36 Ohms at 20°C (68°F).

If resistance is as specified, proceed to next operation check.
If not, replace EGR solenoid vacuum valve.





6) Disconnect vacuum hoses from pipes.
7) Blow into hose "A".
Air should come out of hose "B" and not out of filter.





8) Connect 12V-battery to EGR solenoid vacuum valve terminals. In this state, blow hose "A".
Air should come out of filter and not out of hose "B".
If check result is as described above, check EGR solenoid vacuum valve harness.
If not, replace EGR solenoid vacuum valve.





9) Connect solenoid vacuum valve coupler securely.
10) Connect vacuum hoses securely.

CAUTION: Refer to figure at the left for correct connection of vacuum hoses. Incorrect connection will cause engine malfunction.


EGR Solenoid Vacuum Valve (For System Check) and Its Circuit




Inspection
1) Disconnect vacuum hoses from pipes.
2) Blow into pipe "A" with ignition switch ON.
Air should come out of pipe "B" and not out of pipe "C".
If not, proceed to step 4).





Using SUZUKI scan tool
3) Connect SUZUKI scan tool to DLC and connect vacuum hoses.
- Warm up and stop engine.
- Disconnect vacuum noses from pipes.
- Turn ON EGR solenoid vacuum valve (for system check) by using SUZUKI scan tool with ignition switch ON.
- In this state, blow into pipe "A".
- Air should come out of pipe "C" and not out of pipe "B".If check results are as describe above, EGR solenoid vacuum valve (for system check) and its circuit are in good condition.
- If not, proceed to step 4).

Not using SUZUKI scan tool





3) Using service wire, connect E34-18 (E 174-11) terminal of ECM coupler and body ground with ignition switch OFF.
- Turn ON ignition switch.
- In this state, blow into pipe "A".
- Air should come out of pipe "C" and not out of pipe "B".
- If check results are as described above and E34-18 (E174-11) terminal to ECM connection is OK, EGR solenoid vacuum valve (for system check) and its circuit are in good condition.
- If not, proceed to step 4).





4) With ignition switch OFF, disconnect coupler from EGR solenoid vacuum valve (for system check).
5) Check resistance between two terminals of EGR solenoid vacuum valve (for system check)

Resistance of EGR solenoid vacuum valve (for system check):
37 - 44 Ohms at 20 °C (68 °F)

If resistance is as specified, proceed to step 6). If not, replace.





6) Disconnect vacuum hoses from pipes.
7) Blow into pipe "A". Air should come out of pipe "B" and not out of pipe "C".
If not, replace EGR solenoid vacuum valve (for system check).





8) Connect 12V-battery to EGR solenoid vacuum valve (for system check) terminals. In this state, blow hose "A". Air should come out of filter and not out of hose "B". If check result is as described above, check EGR solenoid vacuum valve (for system check) harness.
If not, replace EGR solenoid vacuum valve (for system check).





9) Connect EGR solenoid vacuum valve (for system check) coupler securely.
10) Connect vacuum hoses securely.

CAUTION: Refer to figure at the left for correct connection of vacuum hoses. Incorrect connection will cause engine malfunction.