Leak Diagnosis
DTC
P0442 Evaporative Emission Control System Leak Detected (Small Leak)
P0457 Evaporative Emission Control System Leak Detected (Fuel Cap Loose/Off)
- The diagnostic 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.
- The diagnosis is divided into the following five phases.
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 kPa (0 → -10.5 mmHg, 0 → -0.4 inHg)
When the pressure above (desired negative pressure) is reached, enters Mode C.
In this case, if the tank pressure does not reach the target negative pressure, judge that there is a large leakage in the system and terminate the evaporative emission control system diagnosis.
Abnormality Judgment
Judge as NG (large leakage) when the following conditions are established.
Judgment Value
| Malfunction Criteria | Threshold Value | DTC |
|---|---|---|
| Time to reach target negative pressure | ≥ 10000 ms + 25000 ms | P0457 |
| or | ||
| Mode B time (Min. pressure value in tank when in mode B) - (Tank pressure when mode B started) | ≥ 10000 ms > -0.5 kPa (-4 mmHg, -0.2 inHg) |
Time Needed for Diagnosis: 5000 ms + 3000 ms + 10000 ms + 10000 ms + 25000 ms
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 change to Mode E when it does not return in spite of spending the specified time.
| Tank pressure when starting calculation of P2 | Time for advanced OK judgment |
|---|---|
| -1.3 kPa (-9.75 mmHg, -0.4 inHg) | 14013 ms |
Time Needed for Diagnosis: 5000 ms + 3000 ms + 10000 ms + 10000 ms + 25000 ms +14013 ms
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.
Abnormality Judgment
Judge as NG when the following conditions are established within the predetermined time. Judge as OK and clear the NG if the following conditions are not established within the predetermined time.
Judgment Value
| Malfunction Criteria | Threshold Value | DTC |
|---|---|---|
| P2 - 1.5 - x P1 | > Value of Map 8 | P0442 |
| P2: Tank pressure that changes every 10000 ms in mode D | ||
| P1: Tank pressure that changes every 10000 ms in mode A | ||
| *1.5 -: Evaporation amount compensation value when below negative pressure (Amount of evaporation occurrence increases as a vacuum condition increases.) | ||
Map 8 Fault criteria limit for Evaporative emission control system diagnosis
| Fuel temperature vs. Fuel level | 15°C(59°F) | 25 °C (77 °F) | 35 °C (95 °F) | 45°C(113°F) |
| 10.5 l (2.77 US gal, 2.31 lmp gal) | 0.3 kPa (2.1 mmHg, 0.1 inHg) | 0.3 kPa (2.1 mmHg, 0.1 inHg) | 0.3 kPa (2.3 mmHg, 0.1 inHg) | 0.3 kPa (2.4 mmHg, 0.1 inHg) |
| 27 l (7.13 US gal, 5.94 lmp gal) | 0.3 kPa (2.32 mmHg, 0.1 inHg) | 0.3 kPa (2.5 mmHg, 0.1 inHg) | 0.4 kPa (2.73 mmHg, 0.1 inHg) | 0.4 kPa (2.88 mmHg, 0.1 inHg) |
| 43 l (11.36 US gal, 9.46 lmp gal) | 0.4 kPa (2.88 mmHg, 0.1 inHg) | 0.4 kPa (2.97 mmHg, 0.1 inHg) | 0.4 kPa (3.23 mmHg, 0.1 inHg) | 0.5 kPa (3.43 mmHg, 0.1 inHg) |
| 59.5 l (15.72 US gal, 13.09 lmp gal) | 0.5 kPa (3.5 mmHg, 0.1 inHg) | 0.5 kPa (3.5 mmHg, 0.1 inHg) | 0.5 kPa (3.5 mmHg, 0.1 inHg) | 0.5 kPa (3.7 mmHg, 0.1 inHg) |
Time Needed for Diagnosis: 5000 ms + 3000 ms + 10000 ms + 10000 ms + 25000 ms + 14013 ms +10000 ms
Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.
DTC
P0456 Evaporative Emission Control System Leak Detected (very small leak)
- The diagnostic 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.
- The diagnosis is divided into the following five phases.
Mode A: (0 point compensation)
When the pressure in the tank is not near 0 mmHg, wait until it returns to 0 point (near 0 mmHg). Shift to mode B when returned to the 0 point. Cancel the diagnosis when 0 point does not return in the specified time.
Mode B: (Negative pressure introduced)
Introduce negative pressure in the intake manifold to the tank.
Approx. 0 → -2 kPa (0 → -15 mmHg, 0 → -0.6 inHg)
When the pressure above (desired negative pressure) is reached, enters Mode C.
When the tank internal pressure does not reach the target vacuum pressure, the diagnosis is cancelled.
Mode C: (Negative pressure maintained)
Stop the introduction of negative pressure. (Wait until the tank pressure returns to the start level of P2 calculation.)
Change to Mode D either when the tank pressure returns to the start level of P2 calculation, or when the predetermined amount of time has passed.
Mode D: (Calculate the amount of negative pressure change)
Monitor the tank pressure in mode D, calculate (P2) the pressure change in the tank, and measure the time (evpdset) for the tank pressure to change to the Mode E shifting pressure. When the Mode E shifting pressure is reached, Mode E is entered. If it does not change to the Mode E shifting pressure after the predetermined amount of time has passed, make advanced OK judgment or cancel the diagnosis.
Normality Judgment
Judge as OK when the following conditions are established.
Judgment Value
| Malfunction Criteria | Threshold Value |
|---|---|
| Advanced OK judgment 1 | |
| Mode D time | ≥ 0 ms + 20000 ms |
| Tank internal pressure | ≤ Value of Map 9 |
| Advanced OK judgment 2 | |
| Mode D time | ≥ 0 ms + Value of Map 10 |
| P2 | ≤ Value of Map 11 |
Map 9
| Fuel level (l , US gal, lmp gal) | 10.5, 2.77, 2.31 | 27, 7.13, 5.94 | 43, 11.36, 9.46 | 59.5, 15.72, 13.09 |
| Tank pressure (kPa, mmHg, inHgl) | -1.9, -14.61, -0.6 | -1.9, -14.61, -0.6 | -1.8, -13.64, -0.5 | -1.8, -13.13, -0.5 |
Map 10
| Fuel level (l , US gal, lmp gal) | 10, 2.64, 2.2 | 20, 5.28, 4.4 | 30, 7.93, 6.6 | 40, 10.57,8.8 | 50, 13.21, 11 | 60, 15.85, 13.2 |
| Time Needed for Diagnosis (ms) | 200000 | 200000 | 200000 | 200000 | 200000 | 200000 |
Map 11
| Fuel level (l , US gal, lmp gal) | 10.5, 2.77, 2.31 | 27, 7.13, 5.94 | 43,11.36, 9.46 | 59.5, 15.72, 13.09 |
| Tank pressure (kPa, mmHg, inHgl) | 1.1, 8.52, 0.3 | 1.1, 8.52, 0.3 | 1.3, 10, 0.4 | 1.3, 10, 0.4 |
Mode E: (Evaporation occurrence amount calculation)
Calculate the change of tank pressure with the time evpdset (P1) to judge as NG/OK according to the value of P1. (ambiguous determination acceptable).
- Abnormality Judgment
Judge as NG when the following conditions are established.
Judgment Value
| Malfunction Criteria | Threshold Value |
|---|---|
| P1 | < Value of Map 12 |
Map 12 Malfunction criteria limit for evaporation diagnosis
| Time (evpdset) vs Fuel level | 40000 ms | 60000 ms | 105000 ms | 110000 ms | 140000 ms | 160000 ms | 180000 ms | 200000 ms |
| 10.5 l (2.77 US gal, 2.31 lmp gal) | 0 kPa (0.00 mmHg, 0 inHg) | 0.1 kPa (0.70 mmHg, 0 inHg) | 0.3 kPa (2.18 mmHg, 0.1 inHg) | 0.3 kPa (2.23 mmHg, 0.1 inHg) | 0.3 kPa (2.53 mmHg, 0.1 inHg) | 0.4 kPa (2.72 mmHg, 0.1 inHg) | 0.4 kPa (2.90 mmHg, 0.1 inHg) | 0.4 kPa (2.90 mmHg, 0.1 inHg) |
| 27 l (7.13 US gal, 5.94 lmp gal) | 0 kPa (0.00 mmHg, 0 inHg) | 0.2 kPa (1.81 mmHg, 0.1 inHg) | 0.3 kPa (2.46 mmHg, 0.1 inHg) | 0.3 kPa (2.53 mmHg, 0.1 inHg) | 0.4 kPa (2.90 mmHg, 0.1 inHg) | 0.4 kPa (2.90 mmHg, 0.1 inHg) | 0.4 kPa (2.90 mmHg, 0.1 inHg) | 0.4 kPa (2.90 mmHg, 0.1 inHg) |
| 43 l (11.36 US gal, 9.46 lmp gal) | 0 kPa (0.00 mmHg, 0 inHg) | 0.2 kPa (1.53 mmHg, 0.1 inHg) | 0.3 kPa (2.49 mmHg, 0.1 inHg) | 0.3 kPa (2.60 mmHg, 0.1 inHg) | 0.3 kPa (2.60 mmHg, 0.1 inHg) | 0.3 kPa (2.60 mmHg, 0.1 inHg) | 0.3 kPa (2.60 mmHg, 0.1 inHg) | 0 kPa (0.00 mmHg, 0 inHg) |
| 59.5 l (15.72 US gal, 13.09 lmp gal) | 0 kPa (0.00 mmHg, 0 inHg) | 0.2 kPa (1.31 mmHg, 0.1 inHg) | 0.3 kPa (2.53 mmHg, 0.1 inHg) | 0.3 kPa (2.53 mmHg, 0.1 inHg) | 0.3 kPa (2.53 mmHg, 0.1 inHg) | 0.3 kPa (2.53 mmHg, 0.1 inHg) | 0.2 kPa (1.26 mmHg, 0 inHg) | 0 kPa (0.00 mmHg, 0 inHg) |
Time needed for diagnosis: Value from Map 1 + Value from Map 2 + Value from Map 3 + 0 ms + Value from Map 4 + 0 ms + Value from Map 4 + Value from Map 5
Malfunction Indicator Light Illumination: Illuminates when malfunction occurs in 2 continuous driving cycles.
- Normality Judgment
Judge as OK when the following conditions are established.
Judgment Value
| Malfunction Criteria | Threshold Value |
|---|---|
| P1 | > Value of Map 13 |
Map 13 Malfunction criteria limit for evaporation diagnosis
| Time (evpdset) vs Fuel level | 20000 ms | 60000 ms | 105000 ms | 110000 ms | 140000 ms | 160000 ms | 180000 ms | 200000 ms |
| 10.5 l (2.77 US gal, 2.31 lmp gal) | 0 kPa (0.00 mmHg, 0 inHg) | 0.3 kPa (2.20 mmHg, 0.1 inHg) | 0.5 kPa (3.68 mmHg, 0.1 inHg) | 0.5 kPa (3.73 mmHg, 0.1 inHg) | 0.5 kPa (4.03 mmHg, 0.2 inHg) | 0.6 kPa (4.22 mmHg, 0.2 inHg) | 0.6 kPa (4.40 mmHg, 0.2 inHg) | 0.6 kPa (4.40 mmHg, 0.2 inHg) |
| 27 l (7.13 US gal, 5.94 lmp gal) | 0 kPa (0.00 mmHg, 0 inHg) | 0.4 kPa (3.31 mmHg, 0.1 inHg) | 0.5 kPa (3.96 mmHg, 0.2 inHg) | 0.5 kPa (4.03 mmHg, 0.2 inHg) | 0.6 kPa (4.40 mmHg, 0.2 inHg) | 0.6 kPa (4.40 mmHg, 0.2 inHg) | 0.6 kPa (4.40 mmHg, 0.2 inHg) | 0.6 kPa (4.40 mmHg, 0.2 inHg) |
| 43 l (11.36 US gal, 9.46 lmp gal) | 0 kPa (0.00 mmHg, 0 inHg) | 0.4 kPa (3.03 mmHg, 0.1 inHg) | 0.5 kPa (3.99 mmHg, 0.2 inHg) | 0.5 kPa (4.10 mmHg, 0.2 inHg) | 0.5 kPa (4.10 mmHg, 0.2 inHg) | 0.5 kPa (4.10 mmHg, 0.2 inHg) | 0.5 kPa (4.10 mmHg, 0.2 inHg) | 0.2 kPa (1.50 mmHg, 0.1 inHg) |
| 59.5 l (15.72 US gal, 13.09 lmp gal) | 0 kPa (0.00 mmHg, 0 inHg) | 0.4 kPa (2.81 mmHg, 0.1 inHg) | 0.5 kPa (4.03 mmHg, 0.2 inHg) | 0.5 kPa (4.03 mmHg, 0.2 inHg) | 0.5 kPa (4.03 mmHg, 0.2 inHg) | 0.5 kPa (4.03 mmHg, 0.2 inHg) | 0.4 kPa (2.76 mmHg, 0.1 inHg) | 0.2 kPa (1.50 mmHg, 0.1 inHg) |
Time needed for diagnosis: Value from Map 1 + Value from Map 2 + Value from Map 3 + 0 ms + Value from Map 4 + 0 ms + Value from Map 4 + Value from Map 5