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| • | 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 of the diagnostic category. |
Circuit | Short to Ground | High Resistance | Open | Short to Voltage | Signal Performance |
|---|---|---|---|---|---|
FTP Sensor Low Reference | - | P0446, P0451 | P0446 | - | P0451 |
FTP Sensor Signal | P0452 | - | P0452 | P0453 | P0451, P0454 |
FTP Sensor 5 V Reference | P0452, P0530, P0641 | P0451 | P0446, P0452 | P0453, P0530, P0641 | - |
Circuit | Normal Range | Short to Ground | Open | Short to Voltage |
|---|---|---|---|---|
Operating Conditions: With EVAP system vented to atmosphere | ||||
FTP Sensor Low Reference | - | 1.5 V | 4.6 V | - |
FTP Sensor Signal | 1.5 V | 0 V | 0 V | 5 V |
FTP Sensor 5 V Reference | - | 0 V | 0 V | 5 V |
The fuel tank pressure (FTP) sensor measures air pressure or vacuum in the evaporative emission (EVAP) system. The engine control module (ECM) supplies a 5 V reference and a low reference circuit to the FTP sensor. The FTP sensor signal voltage varies depending on EVAP system pressure or vacuum. The ECM also uses this FTP signal to determine atmospheric pressure for use in the engine-off small leak test, DTC P0442. Before using this signal as an atmospheric reference it must first be re-zeroed.
| • | DTC P0451 runs only when the engine-off natural vacuum small leak test, P0442, executes. |
| • | The number of times this test runs can range from 0-2 per engine-off period. The length of the test can be up to 10 minutes. |
DTC P0452 and P0453 run continuously when the ignition is ON.
| • | DTC P0454 runs only when the engine-off natural vacuum small leak test, P0442, executes. |
| • | This test can run once per engine-off period. The length of the test can be up to 10 minutes. |
| • | A refuelling event is not detected. |
This DTC will set if the controller is unable to reset thee FTP sensor voltage to zero the within a calibrated range during the engine-off small leak test, P0442.
The FTP sensor voltage is less than 0.1 V for more than 5 s.
The FTP sensor voltage is more than 4.9 V for more than 5 s.
If, during the engine-off natural vacuum small leak test, P0442, the ECM detects an abrupt FTP signal change, other than a refuelling event, this DTC will set. An abrupt change is defined as a change of 1 inch H2O in the span of 1 s.
| • | DTCs P0451 and P0454 are Type A DTCs. |
| • | DTCs P0452 and P0453 are Type B DTCs. |
| • | DTCs P0451 and P0454 are Type A DTCs. |
| • | DTCs P0452 and P0453 are Type B DTCs. |
| • | A restriction in the EVAP canister or vent lines could prevent fuel vapour pressure from bleeding off fast enough. If the vent system cannot bleed off pressure fast enough, the reset to zero procedure may not complete successfully, which could cause this code to set. |
| • | Ensure that the reference port on the FTP sensor is unobstructed. |
| • | An FTP sensor that is skewed or does not have a linear transition from low to high may cause this code to set. Scan tool output controls, snapshot, and plot functions can help detect erratic sensor response. To test the sensor signal under vacuum conditions, use the Quick Snapshot and the Purge/Seal functions to capture data while commanding purge to 20 %, then plot the data to look for erratic sensor operation. A similar test can be done for the pressure side of the sensor operation by applying pressure with the J 41413-200 EEST while taking a snapshot. |
Evaporative Emission Control System Description
Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Control Module References for scan tool information
J 41413-200 Evaporative Emission System Tester (EEST)
| ⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | 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 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 ECM. |
| ⇒ | If greater than the specified range, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the ECM. |
| ⇒ | If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Fuel Tank Pressure Sensor Replacement : LE5 |
| • | Control Module References for engine control module (ECM) replacement, setup, and programming |
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