P0451

DTC P0451: Evaporative Emission Control System Pressure Sensor Performance

Wiring Diagram










DTC Detecting Condition and Trouble Area






DTC Confirmation Procedure

WARNING:

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

NOTE:

Check to make sure that the following conditions are satisfied when using this DTC confirmation procedure.

- Intake air temp.: -14 °C, 6.8 °F or higher.
- Altitude (barometric pressure): 2020 m, 6650 ft or less (540 mmHg, 72 kPa or more).

1) With ignition switch turned OFF, connect scan tool.
2) Turn ON ignition switch and clear DTC using scan tool.
3) Start engine and warm up to normal operating temperature.
4) Drive vehicle at 40 mph 60 km/h or more for 5 min. or more.
5) Stop vehicle and check DTC and pending DTC.

DTC Troubleshooting

WARNING:

In order to reduce risk of fire and personal injury, this work must be performed in a well ventilated area and away from any open flames such as gas hot water.

1.
Was "Engine System Check" performed?
YES
Go to Step 2.
NO
Go to Engine System Check Engine System Check.

2.
Do you have SUZUKI scan tool?
YES
Go to Step 3.
NO
Go to Step 4.

3. Check fuel tank pressure and temp. sensor and its circuit.

Connect SUZUKI scan tool to DLC with ignition switch turned OFF.
Open fuel filler cap and turn ON ignition switch.

Is tank pressure displayed about 0 kPa (0 mmHg)?
YES
Go to Step 17.
NO
Go to Step 5.

4. When not using SUZUKI scan tool: Check fuel tank pressure and temp. sensor circuit.

Open fuel filler cap and turn ON ignition switch.
Check voltage at "G04-32" terminal of ECM connector connected.

Is it about 2.0 - 3.0 V?
YES
Check poor connection at "G04-32" terminal. If OK, go to Step 17.
NO
Go to Step 5.

5. Check fuel tank pressure and temp. sensor power supply voltage.

Remove fuel tank referring to Fuel Tank Removal and Installation Fuel Tank Removal and Installation.
Disconnect connector from fuel tank pressure and temp. sensor with ignition switch turned OFF.
Check proper connection to fuel tank pressure and temp. sensor at "GRY/RED" and "ORN" wire terminals.
If OK, then turn ON ignition switch, check voltage between "GRY/RED" wire terminal in fuel tank pressure and temp. sensor harness connector and vehicle body ground.

Is voltage about 4 - 6 V?
YES
Go to Step 9.
NO
Go to Step 6.

6. Check ECM voltage.

Disconnect connectors from ECM with ignition switch turned OFF.
Remove ECM from vehicle body and connect connectors to ECM.
Check proper connection of connector at "C46-18" terminals.
If OK, then turn ON ignition switch, check voltage between "C46-18" terminal wire and vehicle body ground.

Is voltage about 4 - 6 V at each terminal?
YES
"GRY/RED" wire open circuit.
If wire and connection are OK, go to step 5.
NO
Go to Step 7.

7. Check ECM voltage.

Disconnect connectors from TP sensor and MAP sensor with ignition switch turned OFF.
Turn ON ignition switch, check voltage between "C46-18" terminal wire and vehicle body ground.

Is voltage about 4 - 6 V at each terminal?
YES
Faulty MAP sensor and/or TP sensor.
Check MAP sensor and/or TP sensor.
NO
Go to Step 8.

8. Check wire circuit.

Disconnect connector from ECM with ignition switch turned OFF.
Turn ON ignition switch.
Measure voltage between "GRY/RED" wire terminal in fuel tank pressure and temp. sensor harness connector and vehicle body ground.

Is voltage about 0 V at each terminal?
YES
Go to Step 9.
NO
"GRY/RED" wire shorted to others circuit.
If wire are OK, substitute a known-good ECM and recheck.

9. Check fuel tank pressure and temp. sensor power supply voltage.

Measure resistance between "GRY/RED" wire terminal in fuel tank pressure and temp. sensor harness connector and vehicle body ground.

Is resistance infinity?
YES
Go to Step 10.
NO
"GRY/RED" wire shorted to ground circuit.

10. Check wire circuit.

Measure resistance between "C46-18" terminal in ECM harness connector and "GRY/RED" wire terminal in fuel tank pressure and temp. sensor connector with ignition switch turned OFF.

Is resistance below 5 ohms?
YES
Go to Step 11.
NO
"GRY/RED" wire in high resistance circuit.

11. Check ground circuit.

Connect connector to ECM.
Check proper connection of fuel tank pressure and temp. sensor at "ORN" wire terminal.
Measure resistance between "ORN" wire terminal in fuel tank pressure and temp. sensor connector and body ground.

Is resistance below 10 ohms?
YES
Go to Step 13.
NO
Go to Step 12.

12. Check ground circuit.

Measure resistance between "C46-27" terminal and body ground.

Is resistance below 5 ohms?
YES
"ORN" wire open circuit or high resistance circuit.
Poor "C46-27" connection.
NO
Faulty ECM ground circuit.
If circuit are OK, substitute a known-good ECM and recheck.

13. Check wire circuit.

Disconnect connector from ECM with ignition switch turned OFF.
Turn ON ignition switch.
Measure voltage between "RED/YEL" wire terminal in fuel tank pressure and temp. sensor harness connector and vehicle body ground.

Is voltage about 0 V at each terminal?
YES
Go to Step 14.
NO
"RED/YEL" wire shorted to other circuits.
If wire are OK, substitute a known-good ECM and recheck.

14. Check fuel tank pressure and temp. sensor signal.

Measure resistance between "RED/YEL" wire terminal in fuel tank pressure and temp. sensor harness connector and vehicle body ground.

Is resistance infinity?
YES
Go to Step 15.
NO
"RED/YEL" wire shorted to ground circuit.

15. Check wire circuit.

Measure resistance between "G04-33" terminal in ECM harness connector and "RED/YEL" wire terminal in fuel tank pressure and temp. sensor connector with ignition switch turned OFF.

Is resistance below 5 ohms?
YES
Go to Step 16.
NO
"RED/YEL" wire in high resistance circuit.

16. Check fuel tank pressure and temp. sensor according to Fuel Tank Pressure and Temp. Sensor Inspection Fuel Tank Pressure and Temp. Sensor Inspection.

Is it in good condition?
YES
Substitute a known-good ECM and recheck.
NO
Replace fuel tank pressure and temp. sensor.

17.
Check the following parts for clog.
Check the EVAP canister.
Check the EVAP canister air suction filter.
Check the EVAP canister air suction passage.
Check the Fuel vapor passage between tank and canister.

Is check result satisfactory?
YES
Intermittent trouble or faulty ECM.
Check for intermittent referring to Intermittent and Poor Connection Inspection.
NO
Clean, repair or replace.