HX: Evaporative Emission (EVAP) Monitor and System

HX: Introduction See: HX: Evaporative Emission (EVAP) Monitor and System - Introduction

HX1 DTC P0443: INSPECT EVAP CANISTER PURGE VALVE CIRCUIT FOR INTERMITTENT FAILURE

• Rerun KOEO, KOER Self-Tests and retrieve Continuous Memory DTCs.

Is DTC P0443 present in Continuous Memory Self-Test only?
Yes

• An intermittent circuit fault may cause a Continuous Memory

DTC P0443. GO to HX2
.

No

• GO to HX2

.

HX2 DTC P0443: CHECK VPWR VOLTAGE TO EVAP CANISTER PURGE VALVE

• Key off.
• Disconnect EVAP canister purge valve.
• Key on, engine off.
• Measure voltage between VPWR circuit at the EVAP canister purge valve harness connector and battery negative post.

Is voltage greater than 10.5 volts?
Yes

• KEY OFF. GO to HX3

.

No

• REPAIR open circuit.

HX3 CHECK EVAP CANISTER PURGE VALVE RESISTANCE

Note: EVAP canister purge valve resistance reading must be taken with engine cooled down.

• Disconnect EVAP canister purge valve.
• Measure EVAP canister purge valve resistance.

Is resistance between 30 and 38 ohms?
Yes

• GO to HX4

.

No

• REPLACE damaged EVAP canister purge valve. COMPLETE an Evaporative

Emission Leak Check Monitor Repair Verification Drive Cycle (REFER to Section
2, Drive Cycles See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods\Drive Cycles).

HX4 CHECK EVAP CANISTER PURGE VALVE CIRCUIT FOR OPEN IN HARNESS

Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

• Disconnect PCM.
• Measure resistance of EVAP canister purge valve circuit between PCM harness connector pin and EVAP canister purge valve harness connector.

Is resistance less than 5.0 ohms?
Yes

• GO to HX5

.

No

• REPAIR open circuit.

HX5 CHECK EVAP CANISTER PURGE VALVE CIRCUIT FOR SHORT TO PWR GND IN HARNESS

• Disconnect scan tool from DLC.
• Measure resistance between EVAP canister purge valve circuit at the EVAP canister purge valve harness connector and battery negative post.

Is resistance greater than 10,000 ohms?
Yes

• GO to HX6

.

No

• REPAIR short circuit.

HX6 CHECK EVAP CANISTER PURGE VALVE CIRCUIT FOR SHORT TO VPWR IN HARNESS

• Key on, engine off.
• Measure voltage between EVAP canister purge valve circuit at the EVAP canister purge valve harness connector and battery negative post.

Is voltage greater than 10.5 volts?
Yes

• REPAIR short circuit.

No

• The fault that produced Continuous Memory DTC P0443 can be intermittent.

GO to Z1 See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 5: Pinpoint Tests\Z: Intermittent - Pinpoint Test

0. If OK REPLACE PCM (refer to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) See: Programming and Relearning\Flash Electrically Eraseable Programmable Read Only Memory - Flash EEPROM).

HX18 DTC P1450: CHECK FOR VISUAL CAUSES OF EXCESSIVE FUEL TANK VACUUM

Note: If the EVAP canister-CV solenoid and fuel tank assemblies are not accessible during this pinpoint test step, GO to Evaporative Emissions System for removal instructions.

• Check for kinks or bends in the fuel vapor hoses/tubes (EVAP canister purge outlet tube and EVAP canister tube).
• Visually inspect EVAP canister inlet port, CV solenoid filter and canister vent hose assembly for contamination or debris.
• Check CV solenoid filter for blockage or contamination.

Is a fault indicated?
Yes

• REMOVE any contamination or debris around fuel vapor hoses/tubes

and EVAP canister- CV solenoid assembly. REMOVE kinks or bends in EVAP canister
purge outlet tube, EVAP canister tube and canister vent hose assembly. GO to HX19
.

No

• GO to HX19

.

HX19 CHECK FUEL TANK PRESSURE SENSOR VOLTAGE

• Connect scan tool.
• Key on, engine off.
• Access the FTP V PID.

Is the FTP V PID between 2.40 to 2.80 volts with the fuel filler cap on?
Yes

• A possible intermittent condition on the FTP sensor circuit

can cause the DTC P1450. GO to Z1 See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 5: Pinpoint Tests\Z: Intermittent - Pinpoint Test. If circuit is OK, REFER to Evaporative Emissions System for a blocked (plugged) EVAP system condition.

No

• KEY OFF. GO to HX20

.

HX20 CHECK FUEL TANK PRESSURE SENSOR VOLTAGE WITH FUEL FILLER CAP REMOVED

• Remove the fuel filler cap.
• Key on, engine off.
• Access the FTP V PID.

Is the FTP V PID between 2.40 to 2.80 volts with fuel filler cap off?
Yes

• REFER to Evaporative Emissions, Section 303-13, in the Workshop

Manual for a blocked (plugged) EVAP system condition.

No

• KEY OFF. GO to HX21

.

HX21 CHECK FOR OTHER DTCS PRESENT

• Check for other three wire sensor DTCs (KOEO, KOER or Continuous Memory) present with the DTC P1450.

Are other DTCs present?
Yes

• RETURN to Diagnostic Subroutines, Section 4 See: A L L Diagnostic Trouble Codes ( DTC )\Testing and Inspection\Diagnostic Trouble Code Descriptions, for

direction in addressing the other DTCs.

No

• KEY OFF. GO to HX22

.

HX22 CHECK VREF FROM PCM TO FTP SENSOR

• Disconnect FTP sensor.
• Key on, engine off.
• Measure voltage between VREF and SIG RTN circuits at the FTP sensor harness connector.

Is voltage between 4.0 and 6.0 volts?
Yes

• KEY OFF. REPLACE damaged FTP sensor. CLEAR Continuous Memory

DTCs. FOLLOW the Vehicle Preparation for Monitor Repair Verification Drive
Cycle and COMPLETE an Evaporative Emission Leak Check Monitor Repair Verification
Drive Cycle (REFER to Section 2, Drive Cycles See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods\Drive Cycles).
RETRIEVE Continuous Memory DTCs. If DTC P1450 is still present, REFER to Evaporative Emissions System.

No

• KEY OFF. GO to HX23

.

HX23 CHECK FOR OPEN VREF AND SIG RTN CIRCUITS BETWEEN PCM AND FTP SENSOR

Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

• Disconnect PCM.
• Measure resistance of VREF circuit between PCM harness connector pin and FTP sensor harness connector.
• Measure resistance of SIG RTN circuit between PCM harness connector pin and FTP sensor harness connector.

Is each resistance less than 5.0 ohms?
Yes

• REPLACE PCM (REFER to Section 2, Flash Electrically Erasable Programmable Read Only Memory (EEPROM) See: Programming and Relearning\Flash Electrically Eraseable Programmable Read Only Memory - Flash EEPROM).

No

• REPAIR open circuit.

HX26 DTC P0452: CHECK FOR FTP SENSOR CONNECTOR CONTAMINATION

• Key off.
• Visually check for contamination of the FTP sensor electrical connector.
• Check for completely submerged FTP sensor (tank mounted type only) in liquid fuel (can affect correct FTP voltage reading).

Does FTP sensor and its electrical connector show signs of contamination?
Yes

• REPAIR FTP sensor electrical connector as necessary.

No

• GO to HX27

.

HX27 CHECK FOR LOW FTP SENSOR VOLTAGE

Note: FTP sensor input with no pressure/vacuum on the fuel tank (filler cap open or not open to atmosphere) is between 2.37 and 2.97 volts.

• Connect scan tool.
• Key on, engine off.
• Access FTP V PID.
• If FTP V PID is not present on the scan tool, measure voltage between FTP and SIG RTN circuits at the PCM harness connector with PCM connected.

Is measured voltage or FTP V PID reading less than 0.22 volt?
Yes

• KEY OFF. GO to HX28

.

No

• The fault that produced the DTC P0452 is intermittent. GO to Z1 See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 5: Pinpoint Tests\Z: Intermittent - Pinpoint Test

.

HX28 CHECK OPPOSITE INDUCED HIGH FTP SIGNAL

• Disconnect FTP sensor.
• Connect a jumper wire between VREF circuit and FTP circuits at the FTP sensor harness connector.
• Key on, engine off.
• If a scan tool communication concern exists, remove jumper immediately and GO to HX29.
• Access FTP V PID.
• If FTP V PID is not present on the scan tool, measure voltage between FTP and SIG RTN circuits at the PCM harness connector with PCM connected.

Is measured voltage or FTP V PID reading between 4.0 and 6.0 volts?
Yes

• REPLACE FTP sensor. REFER to Evaporative Emissions System for component removal and installation. RESTORE

vehicle. FOLLOW the Vehicle Preparation for Monitor Repair Verification Drive
Cycle and COMPLETE an Evaporative Emission Leak Check Monitor Repair Verification
Drive Cycle (REFER to Section 2, Drive Cycles See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods\Drive Cycles).

No

• REMOVE jumper. GO to HX29

.

HX29 CHECK VOLTAGE BETWEEN VREF AND SIG RTN CIRCUITS AT FTP SENSOR

• Key on, engine off.
• Measure voltage between VREF and SIG RTN circuits at the FTP sensor harness connector.

Is voltage between 4.0 and 6.0 volts?
Yes

• KEY OFF. GO to HX30

.

No

• VREF voltage is out of range. GO to C1 See: C: Reference Voltage - Pinpoint Test

.

HX30 CHECK FTP CIRCUIT FOR SHORT TO SIG RTN OR PWR GND IN HARNESS

Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

• Disconnect PCM.
• Disconnect scan tool from DLC.
• Measure resistance between FTP and SIG RTN circuits at the PCM harness connector.
• Measure resistance between FTP circuit at the PCM harness connector and battery negative post.

Is each resistance greater than 10,000 ohms?
Yes

• REPLACE PCM (REFER to Section 2, Drive Cycles See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods\Drive Cycles).

No

• REPAIR short circuit.

HX33 DTC P0453: CHECK FOR HIGH FTP SENSOR VOLTAGE

Note: FTP sensor input with no pressure/vacuum on the fuel tank (fuel filler cap open or not open to atmosphere) is 2.37 to 2.97 volts.

• Connect scan tool.
• Key on, engine off.
• Access FTP V PID.
• If FTP V PID is not present on the scan tool, measure voltage between FTP and SIG RTN circuits at the PCM harness connector with PCM connected.

Is measured voltage or FTP V PID reading greater than 4.50 volts?
Yes

• KEY OFF. GO to HX34

.

No

• The fault that produced DTC P0453 is intermittent. GO to Z1 See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 5: Pinpoint Tests\Z: Intermittent - Pinpoint Test

.

HX34 CHECK FTP CIRCUIT FOR SHORT TO POWER

• Disconnect FTP sensor.
• Key on, engine off.
• Measure voltage between FTP circuit at the FTP sensor harness connector and battery negative post.

Is the voltage greater than 10.5 volts?
Yes

• KEY OFF. The FTP is indicating a short to VPWR. GO to HX35

.

No

• KEY OFF. GO to HX36

.

HX35 CHECK FTP CIRCUIT FOR SHORT TO VPWR IN HARNESS

Note: Refer to the PCM connector pin numbers in the beginning of this pinpoint test.

• Disconnect PCM.
• Key on, engine off.
• Measure the voltage between FTP circuit at the PCM harness connector and battery negative post.

Is voltage greater than 10.5 volts?
Yes

• REPAIR short circuit.

No

• REPLACE PCM. (REFER to Section 2 See: Diagnostic Trouble Code Tests and Associated Procedures\SECTION 2: Diagnostic Methods

, Flash EEPROM.)

Continued: See: HX36 - HX89