SAAB WIS ONLINE

P1455

Symptom: Market US/CA: CHECK ENGINE Possible smell of petrol. Possible faulty readings on the fuel gauge in the MIU.

P1455


EVAP Tank Pressure Sensor. Serious Leakage in system and malfunctional fuel level sensor.



Fault symptoms


• Market US/CA: CHECK ENGINE

• Possible smell of petrol.

• Possible faulty readings on the fuel gauge in the MIU.


On-Board Diagnostics

Type of diagnosis:


- Once per driving cycle. Interrupted when fault criteria fulfilled or OK reported. Restarts next driving cycle.


Test 1, Cold start

Enable criteria


- Coolant Temperature when starting is between 5-40°C. The difference between coolant temperature and intake air temperature is less then 5°C.

If the above conditions are not fulfilled, Test 2 (warm start) will start.

Idling speed. Max. one change of status of the brake light switch. Purging adaptation higher than -15%. Intake air pressure at least 20 kPa lower than the barometric pressure. Vehicle at a standstill for 5 seconds. The volume of fuel in tank between 9-54 litres. Battery voltage between 10-16 volts. Tank pressure between -300 and +100 Pa.

When the above conditions are fulfilled for more than 5 sec. the diagnosis will start. Should the diagnosis be interrupted the speed must exceed 0 at one stage before the diagnosis is allowed to be restarted. The diagnosis is divided in three phases, A-C:

Phase A) Evaporation check The shut-off valve is activated (closed) at the same time as any purging is interrupted for 4.5 sec. The tank pressure is observed, decreasing pressure reveals a leaking canister purge valve. Increasing pressure by more than 3 Pa/s hints at fuel evaporation, in these cases Phase A should be repeated. If it then continues to rise by more than 3 Pa/s quit the diagnosis. To be able to continue, vehicle speed is required for a short time. When the pressure increases less then 3 Pa/s Phase A is complete. The diagnosis continues to Phase B (pressure decrease)

Phase B) Pressure decrease Shut-off valve is still closed, canister purge valve pulse ratio is set to 23-24.5% until the tank pressure has reached -600 Pa. This decrease in pressure should take Max. 30 sec.

Phase C) Maintaining pressure The shut-off valve is still closed, canister purge valve is closed. The tank pressure is observed for max. 12 sec.


Test 2, warm start

Enable criteria


- The following conditions should be fulfilled within 5 sec. to be able to start the diagnosis: Coolant Temperature and inlet air temperature when starting exceeding +40°C and the difference between coolant temperature and inlet air temperature greater than 5°C.

Idling speed. Max. one change of status of the brake light switch. Purging adaptation higher than -6%. Tank pressure between -300 and +100 Pa. Inlet air pressure at least 20 kPa lower than the atmospheric pressure. The vehicle stationery.The volume of fuel in the tank 9-54 litres. Battery voltage between 10-16 Volts. Tank pressure sensor diagnosis should report OK.

When the above conditions are fulfilled for more than 5 sec. the diagnosis will start. The diagnosis will be interrupted if the purge adaptation exceeds -8%. Should the diagnosis be interrupted the speed must exceed 0 on one occasion before the diagnosis is allowed to be restarted. The diagnosis is divided into three phases, A-C:

Phase A) Evaporation check The shut-off valve is activated (closed) at the same time as any purging is interrupted for 4.5 sec. The tank pressure is observed, decreasing pressure reveals a leaking canister purge valve. Increasing pressure by more than 4 Pa/s hints at fuel evaporation, in these cases Phase A should be repeated. If it then continues to rise by more than 4 Pa/s quit the diagnosis. To be able to continue, vehicle speed is required for a short time. When the pressure increases less then 4 Pa/s Phase A is complete. The diagnosis continues to Phase B (pressure decrease)

Phase B) Pressure decrease Shut-off valve is still closed, canister purge valve pulse ratio is set to 18% until the tank pressure has reached -600 Pa. This decrease in pressure should take Max. 30 sec.

Phase C) Maintaining pressure The shut-off valve is still closed, canister purge valve is closed. The tank pressure is observed for max. 12 sec.


Test 3, Fuel filler cap test

Enable criteria


- The vehicle speed exceeds 40 km/h. Intake air pressure at least 25 Pa less than the atmospheric pressure. The air mass flow through the engine exceeding 10 g/s and that the air mass flow during the diagnosis remains in the interval 85-150% of the value at the start of the diagnosis. Canister purge valve pulse width lies between 50-65%. The purging adaptation lies between -10 to -20%. The volume of petrol between 9-40 litres. Tank pressure between -300 and 100 Pa or that the test has been started.

If the conditions are fulfilled the shut-off valve is closed and the purging is locked on the value it had at the start of the diagnosis (50-65%). If the pressure does not decrease to -500Pa within 6 seconds three times while driving, the fault should be reported.


Fault criteria

Test 1, Cold start


- Phase A) Evaporation check If the pressure decreases by more than 27.5 Pa/s then an internal leakage in the canister purge valve has been detected. If the pressure increases by more than 3 Pa/s then you have major fuel evaporation, in these cases Phase A will be repeated once. If it then continues to rise by more than 3 Pa/s quit the diagnosis. To enable the diagnosis to be restarted the vehicle must be put in motion. When the pressure increases less than 3 Pa/s the diagnosis should continue to Phase B.

- Phase B) Pressure decrease If the pressure cannot be decreased to -450 Pa within 15 seconds or if the pressure reaches -450 Pa within 15 seconds but not as low as -600 Pa within a further 15 seconds (total 30 sec.) then a major leakage has been found.

- Phase C) Maintaining pressure If the pressure increases to -450 Pa within 12 seconds then a small leakage has been found.


Fault criteria

Test 2, warm start


- Phase A) Evaporation check If the pressure decreases by more than 27.5 Pa/s then an internal leakage in the canister purge valve has been detected. If the pressure increases by more than 4 Pa/s then you have major fuel evaporation, in these cases Phase A will be repeated once. If it then continues to rise by more than 4 Pa/s quit the diagnosis. To enable the diagnosis to be restarted the vehicle must be put in motion. When the pressure increases less than 4 Pa/s the diagnosis should continue to Phase B.

- Phase B) Pressure decrease If the pressure cannot be decreased to -450 Pa within 15 seconds or if the pressure reaches -450 Pa within 15 seconds but not as low as -600 Pa within a further 15 seconds (total 30 sec.) then a major leakage has been found.

- Phase C) Maintaining pressure If the pressure increases to -450 Pa within 12 seconds then a small leakage has been found.


Generating diagnostic trouble codes


- Diagnostic Trouble Codes are generated when the above fault criteria are fulfilled and the dependants are OK.

In Test 2 (warm start) intake air temperature should also not have been lower than 5°C.

Fuel Level, plausibility diagnosis: Because the fuel level is used as enable critera in certain diagnoses, the control module must know that the fuel level value is plausible. The way it works is that the Trionic receives a bus message ”Fuel level XX litres" from the MIU. During driving the Trionic observes the value and as the car is driven, fuel is consumed. The Trionic makes sure the fuel level value drops. In the Trionic a number of important filtrations are carried out to avoid faults caused by, for instance, splashing fuel in the tank, starting uphill. The fuel level diagnosis can be called a support diagnosis as it does not generate a DTC, but if for instance the EVAP Purge valve diagnosis has reported a major leakage in the EVAP canister purge valve then DTC P0455 is normally generated. If on the other hand the tank integrity diagnosis has reported the same fault and the fuel level diagnosis has simultaneously reported a fault then DTC P1455 is generated instead.

P0441, P1441 are generated if faults are reported during Phase A

P0455, P1455 are generated if faults are reported during Phase B

P0442, P1442 are generated if faults are reported during Phase C


Fault criteria

Test 3, Fuel filler cap test


- If faults are reported and the engine start temperature is between 5-40°C, Diagnostic Trouble Code P0455 or P1455 will be generated


Dependents


- P0444, P0445, P0501, P0502, P0506, P0507, P1444, P1445, P1576, P1577 and (cars equipped with TCS) P1925.


OK report


- If all conditions are fulfilled and the diagnosis carried out without finding any faults OK will be reported.

Note

Diagnostic trouble codes P0442, P0455, P1442 and P1455 are cleared directly if OK is reported from the diagnosis.



Fault handling

(For more information, see Fault handling III, other emission-related components and functions )

Diagnostic help

Fault diagnosis concerns a leak.

Functions in the diagnostic tool related to the fault:


• Diagnostic status for the diagnosis.

• Activating EVAP diagnosis.


For more information, see Menu "Activate" .

Note

For a final check of the faults that have been taken care of, the diagnostic tool activating command should be used when Test 1 (cold start) is initiated regardless of the starting temperature.