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DTC P1458-P145A

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    •  Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    • Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC P1458: Evaporative Emission (EVAP) System Leak Detection Pump Pressure Sensor Performance

DTC P1459: Evaporative Emission (EVAP) System Leak Detection Pump Pressure Sensor Circuit Low Voltage

DTC P145A: Evaporative Emission (EVAP) System Leak Detection Pump Pressure Sensor Circuit High Voltage

Circuit/System Description

The evaporative emission (EVAP) system uses a EVAP leak detection pump to test for system leaks. The EVAP leak detection pump assembly consists of three main components:

    • EVAP leak detection pump with reference orifice
    • EVAP leak detection pump switching valve
    • EVAP leak detection pump pressure sensor

The EVAP leak detection pump pressure sensor performs a correlation to barometric pressure (BARO). After a short delay period, the EVAP leak detection pump pressure sensor, absolute, reading is compared to the BARO. Large deviations will increment the fail counter threshold and sets a P1458.

There are two different threshold calibrations used in the comparison to the BARO. A smaller threshold is used when there has been a recent BARO update and then a larger threshold value is used when there has not been a recent BARO update.

Conditions for Running the DTC

P1458

Condition 1:

    • DTCs P043E, P043F, P0101, P0102, P0103, P0106, P0107, P0108, P0111, P0112, P0113, P0114, P0116, P0117, P0118, P0119, P0121, P0122, P0123, P0128, P145A, P145C, P145D, P145E, P145F, P012B, P012C, P012D, P0222, P0223, P0443, P0449, P0451, P0452, P0453, P0458, P0459, P0461, P0462, P0463, P0498, P0499, P0502, P0503, P06E4, P0722, P0723, P1221, P1458, P1459, P2066, P2067, P2068, P2400, P2401, P2402, P2418, P2419, P2420, P2421, P2422, P2450, P2537, P2610, U0073, U0074, U0140, U182D is not set.
    • The barometric pressure (BARO) is between than 70-110 kPa (10-16 PSI).
    • The fuel level is between 10-90%.
    • The propulsion system is not active.
    • The engine coolant temperature (ECT) is less than 40°C (104°F).
    • The inlet air temperature (IAT) is between 4-45°C (39-113°F).
    • The battery voltage is greater than 10 V.
    • Vehicle speed is less than 1.6 km/h (1 MPH).
    • No ignition key up during this test.
    • No refuelling request button is pressed.
    • A service bay test is not active.
    • The device control exceeds 0.5 seconds
    • There are three possible time windows for this test to run. Up to that point and through this time period the propulsion system must not be active. These time windows are: 5.0, 7.0 or 9.5 hours.

Condition 2:

    • DTCs P0068, P0071, P0072, P0073, P0101, P0102, P0103, P0106, P0107, P0108, P010C, P010D, P0111, P0112, P0113, P0114, P0121, P0122, P0123, P012B, P012C, P012D, P0222, P0223, P0442, P0443, P0449, P0452, P0453, P0455, P0458, P0459, P0498, P0499, P0502, P0503, P0606, P0722, P0723, P16F3, P1104, P1221, P1458, P1459, P145A, P145D, P145E, P2100, P2101, P2102, P2103, P2400, P2401, P2402, P2418, P2419, P2420, P2422, P2450 is not set.
    • The barometric pressure (BARO) is between 70-110 kPa (10-16 PSI).
    • The outside air temperature (OAT) is between 4-35°C (39-102°F).
    • The propulsion system is active and the engine is running.
    • The system voltage is greater than 11 V.
    • The purge is not enabled.
    • A refueling request button is not pressed.
    • The device control exceeds 0.5 seconds.
    • The FTP sensor performance diagnostic P0451 is running.
    • The EVAP system no purge flow diagnostic P0497 is running.

P1459 and P145A

Runs any time the ECM is awake and the propulsion system is active or not active.

Conditions for Setting the DTC

P1458

    • When the propulsion system is not active - If the difference between the EVAP system leak detection pump pressure sensor, absolute, reading and the BARO value is 3 kPa (0.44 PSI) for 14 s.
    • When the propulsion system is active, and after a stabilisation time of 10 s - When a recent BARO update has occurred within the last 0.1 km (0.06 mi), if the difference between the EVAP system leak detection pump pressure sensor, absolute, reading and the BARO value from the MAP sensor is 15 kPa (2.17 PSI).
    • When a recent BARO update has not occurred within the last 0.1 km (0.06 mi) - If the difference between the EVAP system leak detection pump pressure sensor, absolute, reading and the BARO value from the MAP sensor is 20 kPa (2.9 PSI).

P1459

The ECM detects that the EVAP system leak detection pump pressure sensor signal is less than 0.7 V for greater than 8 s.

P145A

The ECM detects that the EVAP system leak detection pump pressure sensor signal is greater than 4.85 V for greater than 8 s.

Action Taken When the DTC Sets

DTCs P1458, P1459 and P145A are Type B DTCs.

Conditions for Clearing the DTC

DTCs P1458, P1459 and P145A are Type B DTCs.

Diagnostic Aids
    • A normal BARO reading of the vehicle's geographic location will help to determine if a BARO sensor is significantly off its reading.
    • The diagnostic does not run when purge is enabled because it can influence the EVAP leak detection pump pressure sensor reading if there is any restriction in the fresh air plumbing.
    • Test for a plugged 5 micron in-line vent filter between the EVAP system leak detection pump and the fuel fill neck.
    • This diagnostic is disabled when P0451 or P0497 is currently running.

Reference Information

Schematic Reference

Engine Controls Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Evaporative Emission Control System Description

Hybrid Modes of Operation Description

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

DTC Type Reference

Powertrain Diagnostic Trouble Code (DTC) Type Definitions

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification
  1. Vehicle in Service Mode, compare the BARO reading against the EVAP leak detection pump sensor reading with a scan tool. Compare this to the Altitude vs. Barometric Pressure Table referenced here Altitude Versus Barometric Pressure .
    2. ⇒A variance of more than 3 kPa (0.44 PSI) indicates a skewed BARO or EVAP leak detection pump sensor.
  2. Operate the vehicle within the conditions for running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the freeze frame/failure records data.

Circuit/System Testing
  1. Vehicle OFF, disconnect the harness connector at the Q63 EVAP system leak detection pump assembly.

    2. Note: Testing for steps 2-5 is performed on the ECM side of the harness connector.

  2. Vehicle OFF, all systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Test for less than 5 Ω between the Q63 EVAP system leak detection pump pressure sensor low reference circuit terminal 8 and ground.
    3. ⇒If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K20 ECM.
  3. Vehicle in Service Mode, test for 4.8-5.2 V between the Q63 EVAP system leak detection pump 5 V reference circuit terminal 6 and ground.
    4. ⇒If less than the specified range, test the 5 V reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.
    ⇒If greater than the specified range, test the 5 V reference circuit for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  4. Verify the scan tool EVAP leak detection pump pressure sensor parameter is less than 0.2 V.
    5. ⇒If greater than the specified range, test the Q63 EVAP system leak detection pump signal circuit terminal 7 for a short to voltage. If the circuit tests normal, replace the K20 ECM.
  5. Install a 3 A fused jumper wire between the Q63 EVAP system leak detection pump signal circuit terminal 7 and the 5 V reference circuit terminal 6. Verify the scan tool EVAP leak detection pump pressure sensor parameter is greater than 4.7 V.
    6. ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K20 ECM.

    Note: Note: Testing for this step is performed on the EVAP leak detection pump assembly side of the harness connector.

  6. Remove the EVAP assembly and test, inspect, and repair the items listed below. If the items test normal, replace the Q63 EVAP system leak detection pump assembly.
    7. • Poor connection at the X351 harness connector
    • Open or shorted 5 V reference circuit
    • Open or shorted sensor signal circuit
    • Open low reference circuit

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Evaporative Emission System Vacuum Leak Detection Pump Replacement
    • Control Module References for ECM replacement, setup, and programming
   


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