• Diagnostic Method
The diagnostic method consists of creating a sealed vacuum in the fuel tank and then determining the presence of leakage from the speed at which the tank internal pressure returns to barometric pressure.
Mode A: (Estimated evaporation gas amount)
Calculate the tank pressure change amount (P1) when using mode A. After calculating P1, switch to mode B.
Mode B: (Negative pressure sealed)
Introduce negative pressure in the intake manifold to the tank.
Approx. 0 → -1.4 (0 → -10.5, 0 → -0.41) kPa (mmHg, inHg)
When the pressure above (desired negative pressure) is reached, enters Mode C.
In this case, if the tank pressure does not become the desired negative pressure, judge that there is a large leakage (10 seconds or 35 seconds) in the system.
Abnormality Judgment
Judge as NG (large leak) when the criteria below are met.
Judgment Value
| Malfunction Criteria | Threshold Value | DTC |
|---|---|---|
| Time to reach target negative pressure | ≥ 35 seconds | P0457 |
| Or mode B time | ≥ 10 seconds | |
| (Min. pressure value in tank when in mode B) - (Tank pressure when mode B started) | < -0.3 kPa (-2.5 mmHg, -O.1 inHg) |
Mode C: (Check pressure rise)
Stop the introduction of negative pressure. (Wait until the tank pressure returns to the start level of P2 calculation.)
Change to Mode D when the tank pressure returns to the start level of P2 calculation.
Judge immediate OK and perform purge control solenoid valve 2 close diagnosis when it does not return after the specified time passed.
| Tank pressure when starting calculation of P2 | Time for advanced OK judgment |
|---|---|
| -1.3 kPa (-9.75 mmHg, -0.38 inHg) | 17 seconds |
Purge control solenoid valve 2 stuck close diagnosis
Perform purge control solenoid valve 2 stuck close diagnosis using the variation gap between the tank pressure at the end of mode C and after mode C.
| Malfunction Criteria | Threshold Value | DTC |
|---|---|---|
| Tank pressure variation after the end of mode C | = 3 seconds < 0.11 kPa (0.86 mmHg, 0.03 inHg) | P0441 |
Mode D: (Measure amount of negative pressure change)
Monitor the tank pressure change amount when using mode D. In this case, the tank pressure increases, (nears barometric pressure) because evaporation occurs. However, if any leakage exists, the pressure increases additionally in proportion to this leakage. The pressure variation of this tank is P2.
After calculating P2, perform a small leak diagnosis according to the items below.
When Mode D is ended
Assign tank variations measured in Mode A and Mode D, P1 and P2, to the formula below, judge small leaks in the system. If the measured judgment value exceeds the threshold value, it is judged to be a malfunction. Judge as NG when the criteria below are completed and Judge as OK when not completed.
Judgment Value
| Malfunction Criteria | Threshold Value | DTC | ||
|---|---|---|---|---|
| P2 - 1.5 x P1 | > Value from Map 7 | P0442 | ||
| P2: Tank pressure that changes every 10 seconds in mode D P1: Tank pressure that changes every 10 seconds in mode A |
(1) Threshold value: Figure (Remaining Fuel vs Tank temperature) | |||
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Map 7 Failure Diagnosis Reference Limit for 0.04 in Leaks for Evaporation Diagnosis
| Fuel temperature & fuel level | 25°C (77°F) | 30°C (86°F) | 35°C (95°F) | 40°C (104°F) | 45°C (113°F) |
|---|---|---|---|---|---|
| 10 L (2.6 US gal, 2.2 lmp gal) | 0.28 kPa (2.1 mmHg, 0.083 inHg) | 0.29 kPa (2.2 mmHg, 0.087 inHg) | 0.31 kPa (2.3 mmHg, 0.090 inHg) | 0.31 kPa (2.35 mmHg, 0.092 inHg) | 0.32 kPa (2.4 mmHg, 0.094 inHg) |
| 20 L (5.3 US gal, 4.4 lmp gal) | 0.31 kPa (2.3 mmHg, 0.090 inHg) | 0.32 kPa (2.4 mmHg, 0.094 inHg) | 0.33 kPa (2.5 mmHg, 0.098 inHg) | 0.35 kPa (2.6 mmHg, 0.102 inHg) | 0.36 kPa (2.7 mmHg, 0.106 inHg) |
| 30 L (7.9 US gal, 6.6 lmp gal) | 0.39 kPa (2.9 mmHg, 0.114 inHg) | 0.41 kPa (3.05 mmHg, 0.120 inHg) | 0.42 kPa (3.15 mmHg, 0.124 inHg) | 0.43 kPa (3.25 mmHg, 0.128 inHg) | 0.45 kPa (3.35 mmHg, 0.134 inHg) |
| 40 L (10.6 US gal, 8.8 lmp gal) | 0.39 kPa (2.9 mmHg, 0.114 inHg) | 0.42 kPa (3.15 mmHg, 0.124 inHg) | 0.44 kPa (3.3 mmHg, 0.130 inHg) | 0.45 kPa (3.4 mmHg, 0.134 inHg) | 0.47 kPa (3.5 mmHg, 0.138 inHg) |
| 50 L (13.2 US gal, 11.0 lmp gal) | 0.43 kPa (3.2 mmHg, 0.126 inHg) | 0.44 kPa (3.3 mmHg, 0.130 inHg) | 0.47 kPa (3.5 mmHg, 0.138 inHg) | 0.48 kPa (3.6 mmHg, 0.142 inHg) | 0.49 kPa (3.7 mmHg, 0.146 inHg) |
Time Needed for Diagnosis: 30 - 100 seconds
0.02-inch Diagnosis
DTC
P0456 Evaporative Emission Control System Leak Detected (very small leak)