EVAP System Monitor Engine Off Components Checks: Notes
Additional malfunctions that are identified as part of the evaporative system integrity check are as follows:
The Canister Purge Valve (CPV) output circuit is checked for opens and shorts (P0443)
NOTE:
that a stuck closed CPV generates a P04ED, a leaking or stuck open CPV generates a P1450.
CANISTER PURGE VALVE CIRCUIT CHECK OPERATION
| DTCs | P0443 - Evaporative Emission System Purge Control "A" Circuit |
| Monitor Execution | engine off, continuous |
| Monitor Sequence | None |
| Sensors OK | Not Applicable |
| Monitoring Duration | 5 seconds to obtain smart driver status |
TYPICAL CANISTER PURGE VALVE CIRCUIT CHECK MALFUNCTION THRESHOLDS
| P0443: open/shorted |
The Evap Fuel Tank Switching Valve (EVAPSV) control circuit is checked for opens and shorts (P2418). For the PHEV, this component is the FTIV (Fuel Tank Isolation Valve). For the HEV, this component is the VBV (Vapor Blocking Valve).
NOTE:
that a stuck closed Evap Switching Valve generates a P2451; a stuck open Evap Switching Valve generates a P2450.
EVAP SWITCHING VALVE CHECK OPERATION
| DTCs | P2418 - Evap Switching Valve Circuit |
| Monitor Execution | Continuous |
| Monitor Sequence | None |
| Sensors OK | Not Applicable |
| Monitoring Duration | 5 seconds to obtain smart driver status |
EVAP SWITCHING VALVE CHECK MALFUNCTION THRESHOLDS
| P2418 (Evap Switching Valve Circuit): open/shorted |
The ELCM Leak Detection Pump Control Circuit is checked for opens and shorts and functionally.
ELCM PUMP CONTROL CHECK OPERATION
| DTCs | P2401 - EVAP System Leak Detection Pump Control Circuit Low P2402 - EVAP System Leak Detection Pump Control Circuit High |
| Monitor Execution | Continuous |
| Monitor Sequence | None |
| Sensors OK | Not Applicable |
| Monitoring Duration | 5 seconds to obtain smart driver status |
TYPICAL ELCM PUMP CONTROL CHECK MALFUNCTION THRESHOLDS
| P2401/P2402 - output driver open/shorted |
ELCM PUMP CONTROL FUNCTIONAL CHECK OPERATION
| DTCs | P2401 - EVAP System Leak Detection Pump Control Circuit Low P2402 - EVAP System Leak Detection Pump Control Circuit High |
| Monitor Execution | during Phase 0 of evap monitor leak check |
| Monitor Sequence | Evap monitor leak detection condition met |
| Sensors OK | not applicable |
| Monitoring Duration | 360 seconds in Phase 0, 5 seconds on Phase 1 |
TYPICAL ELCM PUMP CONTROL FUNCTIONAL CHECK MALFUNCTION THRESHOLDS
| P2401: pressure at the end of 360 sec of warm-up time in Phase 0 too low; > -2.0 in H2
O / -498.18 Pa. P2402: pressure increasing in Phase 1 after pump shut off for 5 sec; > 4.0 in H2 O / 996.35 Pa. |
ELCM PUMP CONTROL FLOW CHECK OPERATION
| DTCs | P043E - EVAP System Leak Detection Reference Orifice Low Flow P043F - EVAP System Leak Detection Reference Orifice High Flow |
| Monitor Execution | once per key off, after entry conditions have been met during pre-key off drive cycle |
| Monitor Sequence | during Phase 0 of evap monitor leak check |
| Sensors OK | not applicable |
| Monitoring Duration | 60 seconds in Phase 0 |
Typical ELCM Pump Control flow check malfunction thresholds
| P043E: stabilized pressure at the end of Phase 0 too low <= -20.2 in H2
O / 5031.6 Pa P043F: stabilized pressure at the end of Phase 0 too high > -2.8 in H2 O / > -697.45 Pa. |
The Evap Leak Detection Pump Vacuum Switching Valve / (Change Over Valve) control circuit is checked for opens and shorts and functionally.
EVAP VACUUM SWITCHING VALVE CIRCUIT CHECK OPERATION
| DTCs | P24BE - EVAP Leak Detection Pump Vacuum Switching Valve Control Circuit Low P24BF - EVAP Leak Detection Pump Vacuum Switching Valve Control Circuit High |
| Monitor Execution | Continuous |
| Monitor Sequence | None |
| Sensors OK | Not Applicable |
| Monitoring Duration | 5 seconds to obtain smart driver status |
EVAP VACUUM SWITCHING VALVE CIRCUIT CHECK MALFUNCTION THRESHOLDS
| P24BE/P24BF - output driver open/shorted |
EVAP VACUUM SWITCHING VALVE FUNCTIONAL CHECK OPERATION
| DTCs | P24C0 - EVAP System Leak Detection Pump Vacuum Switching Valve Stuck On P24C1 - EVAP System Leak Detection Pump Vacuum Switching Valve Performance/Stuck Off |
| Monitor Execution | P24C0 during Phase 0 of evap monitor leak check, P24C1 during Phase 2 of evap monitor leak check |
| Monitor Sequence | Evap monitor leak detection condition met |
| Sensors OK | P0443, P2418, P24BE, P24BF, P2401, P2402, P144B, P04ED, P1450, P24BA, P24BB, P0451, P0452, P0453, P0454, P2610, P0112, P0113, P043E, P043F, P24C0, P24C1, P2450, P2451 P24BC, P2610, P0112, P0113 |
| Monitoring Duration | 65 seconds in Phase 0, 2 seconds in Phase 2 |
EVAP VACUUM SWITCHING VALVE CHECK MALFUNCTION THRESHOLDS
| P24C0: rate of change of pressure too low; < 1.2 in H2
O / 174.36 Pa P24C1: rate of change of pressure too high; > 4.0 in H2 O / 996.35 Pa. |
The EVAP System Leak Detection Pump Pressure Sensor input circuit is checked for opens and shorts, out of range values and noisy readings.
LEAK DETECTION PUMP PRESSURE SENSOR CHECK OPERATION
| DTCs | P24BA - EVAP System Leak Detection Pump Pressure Sensor Circuit Low P24BB - EVAP System Leak Detection Pump Pressure Sensor Circuit High P24B9 - EVAP System Leak Detection Pump Pressure Sensor Circuit Range/Performance P24BC - EVAP System Leak Detection Pump Pressure Sensor Circuit Intermittent (noisy) |
| Monitor Execution | Continuous |
| Monitor Sequence | None |
| Sensors OK | Not Applicable |
| Monitoring Duration | 20 seconds for electrical malfunctions, 10 seconds for noisy sensor test |
TYPICAL LEAK DETECTION PUMP PRESSURE SENSOR CHECK MALFUNCTION THRESHOLDS
| P24BA (Circuit low): < 168.96 in H2
0 / 42.08 kPa. P0453 (Circuit high): > 496.93 in H2 0 / 123.78 kPa. P24B9 (Reference out of range) > -1.5 to -5.5 in H2 O (function of BARO) OR < -17.5 to -21.5 in H2 O (function of BARO) P24BC (noisy): open circuit, short circuit or > 25.0 in H2 O / 6.227 kPa change between samples, sampled every 100 milliseconds, filtered fault level of 25% will set code in 10 seconds |
The Fuel Tank Pressure Sensor input circuit is checked for out of range values (P0452 short, P0453 open), noisy readings (P0454 noisy) and an offset (P0451 offset).
NOTE:
that for the PHEV, this component is the FTPTHP (Fuel Tank Pressure Transducer - High Pressure). For the HEV, this component is the FTPT (Fuel Tank Pressure Transducer).
FUEL TANK PRESSURE SENSOR TRANSFER FUNCTION
| FTP volts = [ Vref * (0.14167 * Tank Pressure) + 2.6250 ] / 5.00 | ||
| Volts | A/D Counts in PCM | Fuel Tank Pressure, Inches H 2 O |
| 0.100 | 20 | -17.82 |
| 0.500 | 102 | -15.0 |
| 1.208 | 247 | -10.0 |
| 2.625 | 464 | 0 |
| 3.475 | 712 | 6.0 |
| 4.750 | 973 | 15.0 |
| 4.90 | 1004 | 16.06 |
HIGH PRESSURE FUEL TANK PRESSURE SENSOR TRANSFER FUNCTION
| FTP volts = [ Vref * (0.015 * Pump Pressure) + 1.15 ] / 5.00 | ||
| Volts | A/D Counts in PCM | Fuel Tank Pressure, Inches H 2 O |
| 0.25 | 51 | -60.0 |
| 0.50 | 102 | -43.33 |
| 1.15 | 235 | 0.00 |
| 2.05 | 419 | 60.00 |
| 3.00 | 614 | 123.33 |
| 4.50 | 921 | 223.33 |
| 4.75 | 970 | 240.0 |
FUEL TANK PRESSURE SENSOR CHECK OPERATION
| DTCs | P0452 - Fuel Tank Pressure Sensor Circuit Low P0453 - Fuel Tank Pressure Sensor Circuit High P0454 - Fuel Tank Pressure Sensor Intermittent/Erratic (noisy) |
| Monitor Execution | Continuous |
| Monitor Sequence | None |
| Sensors OK | Not Applicable |
| Monitoring Duration | 5 seconds for electrical malfunctions, 10 seconds for noisy sensor test |
TYPICAL FUEL TANK PRESSURE SENSOR CHECK MALFUNCTION THRESHOLDS
| P0452 (Fuel Tank Pressure Sensor Circuit Low): < -17.82 in H2
O P0452 (High Pressure Fuel Tank Pressure Sensor Circuit Low): < -60.00 in H2 O P0453 (Fuel Tank Pressure Sensor Circuit High): > 16.06 in H2 O P0453 (High Pressure Fuel Tank Pressure Sensor Circuit High): > 2401.00 in H2 O P0454 (Fuel Tank Pressure Sensor Circuit Noisy): open circuit, short circuit or > 25 in H2 O change between samples, sampled every 100 milliseconds, filtered fault level of 25% will set code in 10 seconds |
FUEL TANK PRESSURES SENSOR OFFSET CHECK OPERATION
| DTCs | P0451(HEV Only) - Fuel Tank Pressure Sensor Range/Performance (offset) |
| Monitor Execution | once per driving cycle |
| Monitor Sequence | No P0443 or P1450, P2402,, P2450, P2451, P2418, P24BF, P24C0 DTCs |
| Sensors OK | Not Applicable |
| Monitoring Duration | < 1 second |
TYPICAL FUEL TANK PRESSURE SENSOR OFFSET CHECK ENTRY CONDITIONS
| Entry Condition | Minimum | Maximum |
| Ignition key on, engine off, engine rpm | 0 rpm | |
| Purge Duty Cycle | 0% | |
| Engine off (soak) time | 240 min | |
| Fuel Tank Pressure Sensor Variation during test | 0.5 in H2 O | |
| Battery Voltage | 11.0 volts | |
| Not a refueling event | ||
| Tank Pressure | -17.8 In H2 O | 16 In H2 O |
TYPICAL FUEL TANK PRESSURE SENSOR OFFSET CHECK MALFUNCTION THRESHOLDS
| Fuel tank pressure at key on, engine off is 0.0 in H2 O +/- 1.7 in H2 O |
The Fuel Level Input is checked for out of range values (opens/ shorts). The FLI input is obtained from the serial data link from the instrument cluster. If the FLI signal is open or shorted, the appropriate DTC is set, (P0462 circuit low and P0463 circuit high).
Finally, the Fuel Level Input is checked for noisy readings. If the FLI input changes from an in-range to out-of-range value repeatedly, a P0461 DTC is set.
FUEL LEVEL INPUT CHECK OPERATION
| DTCs | P0460 - Fuel Level Sensor A Circuit P0461 - Fuel Level Sensor A Circuit Noisy P0462 - Fuel Level Sensor A Circuit Low P0463 - Fuel Level Sensor A Circuit High |
| Monitor Execution | continuous |
| Monitor Sequence | None |
| Sensors OK | Not Applicable |
| Monitoring Duration | 30 seconds for electrical malfunctions |
TYPICAL FUEL LEVEL INPUT CHECK MALFUNCTION THRESHOLDS
| P0460 or P0462 (Fuel Level Input Circuit Low): < 5 ohms (< 1 A/D count) P0460 or P0463 (Fuel Level Input Circuit High): > 200 ohms (>1022 A/D counts) P0461 (Fuel Level Input Noisy): > 40% change between samples, > 100 occurrences, sampled every 0.100 seconds |
The FLI signal is also checked to determine if it is stuck. "Fuel consumed" is continuously calculated based on PCM fuel pulsewidth summation as a percent of fuel tank capacity. (Fuel consumed and fuel gauge reading range are both stored in KAM and reset after a refueling event or DTC storage.) If the there is an insufficient corresponding change in fuel tank level, a P0460 DTC is set.
Different malfunction criteria are applied based on the range in which the fuel level sensor is stuck.
In the range between 6% and 93%, a 17.5% difference between fuel consumed.
In the range below 6%, a 27.5% difference between fuel consumed.
In the range above 93%, a 80.5% difference between fuel consumed.
FUEL LEVEL INPUT STUCK CHECK OPERATION
| DTCs | P0460 - Fuel Level Input Circuit Stuck |
| Monitor Execution | Continuous |
| Monitor Sequence | None |
| Sensors OK | Not Applicable |
| Monitoring Duration | Between 6 and 93%, monitoring can take from 100 to 120 miles to complete |
TYPICAL FUEL LEVEL INPUT STUCK CHECK MALFUNCTION THRESHOLDS
| P0460 (Fuel Level Input Stuck): Fuel level stuck at greater than 93%: > 80.5% difference in calculated fuel tank capacity consumed versus change in fuel level input reading Fuel level stuck at less than 6%: > 27.5% difference in calculated fuel tank capacity consumed versus change in fuel level input reading Fuel level stuck between 6% and 93%: > 17.5% difference in calculated fuel tank capacity consumed versus change in fuel level input reading |