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DTC P0451: FTP Sensor Range/Performance Problem Honda CR-V II

Auxiliary Emission Control Systems 25 illustrations ~1487 words

Special Tools Required

Vacuum pump/gauge, 0-30 in.Hg A973X-041-XXXXX

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Scheme 26: DTC P0451: FTP Sensor Range/Performance Problem
Scheme 26: DTC P0451: FTP Sensor Range/Performance Problem

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  1. Remove the fuel fill cap.
  2. Turn the ignition switch ON (II).
  3. Monitor fuel tank pressure (FTP) sensor voltage with the HDS, or measure voltage between ECM/PCM connector terminals E4 and E14. Is there about 2.5 V? YES - Go to step 4. NO - Replace the FTP sensor.
  4. Turn the ignition switch OFF.
  5. Disconnect the hose between the EVAP two way valve and the FTP sensor at the EVAP two way valve end.
  6. Connect a vacuum pump to the open end of the hose.
  7. Turn the ignition switch ON (II).
  8. Monitor FTP sensor voltage with the HDS, or measure voltage between ECM/PCM connector terminals E4 and E14, and slowly squeeze the vacuum pump one time.
  9. The voltage should drop smoothly from about 2.5 V down to about 1.5 V. Stop applying vacuum when the voltage drops to about 1.5 V or damage to the FTP sensor may occur. Does the voltage drop to about 1.5 V and hold? YES - Check for a misrouted, leaking, or broken FTP sensor vacuum line. If the vacuum line is OK, update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck (see «GENERAL TROUBLESHOOTING INFORMATION»(ref-171385-S32412467942005020300000) ). If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM. NO - Replace the FTP sensor.

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Scheme 29: DTC P0452: FTP Sensor Circuit Low Voltage
Scheme 29: DTC P0452: FTP Sensor Circuit Low Voltage

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  1. Check the vacuum lines at the FTP sensor for misrouting, leakage, breakage, or clogging. Are the vacuum lines OK? YES - Go to step 2. NO - Repair or replace vacuum lines as necessary.
  2. Reset the ECM/PCM (see «HOW TO RESET THE ECM/PCM»(ref-171385-S07999163522005020300000) ).
  3. Remove the fuel fill cap.
  4. Turn the ignition switch ON (II).
  5. Monitor FTP sensor voltage with the HDS, or measure voltage between body ground and ECM/PCM connector terminal E14. Is there about 2.5 V? YES - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the FTP sensor and at the ECM/PCM. NO - Go to step 6.
  6. Turn the ignition switch OFF.
  7. Reinstall the fuel fill cap.
  8. Disconnect the FTP sensor 3P connector.
  9. Turn the ignition switch ON (II).
  10. Measure voltage between FTP sensor 3P connector terminals No. 1 and No. 2. Is there about 5 V? YES - Go to step 11. NO - Repair open in the wire between the FTP sensor and the ECM/PCM (E5).
  11. Measure voltage between FTP sensor 3P connector terminals No. 2 and No. 3. Is there about 5 V? YES - Replace the FTP sensor. NO - Go to step 12.
  12. Turn the ignition switch OFF.
  13. Disconnect ECM/PCM connector E (31P).
  14. Check for continuity between FTP 3P connector terminal No. 3 and body ground. Is there continuity? YES - Repair short in the wire between the FTP sensor and the ECM/PCM (E14). NO - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck (see «HOW TO RESET THE ECM/PCM»(ref-171385-S07999163522005020300000) ). If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.

Scheme 33

Scheme 33: DTC P0453: FTP Sensor Circuit High Voltage
Scheme 33: DTC P0453: FTP Sensor Circuit High Voltage

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  1. Check the vacuum lines at the FTP sensor for misrouting, leakage, breakage, or clogging. Are the vacuum lines OK? YES - Go to step 2. NO - Repair or replace vacuum lines as necessary.
  2. Reset the ECM/PCM (see «HOW TO RESET THE ECM/PCM»(ref-171385-S07999163522005020300000) ).
  3. Remove the fuel fill cap.
  4. Turn the ignition switch ON (II).
  5. Monitor FTP sensor voltage with the HDS, or measure voltage between body ground and ECM/PCM connector terminal E14. Is there about 2.5 V? YES - Intermittent failure, system is OK at this time. Check for poor connections or loose terminals at the FTP sensor and at the ECM/PCM. NO - Go to step 6.
  6. Turn the ignition switch OFF.
  7. Reinstall the fuel fill cap.
  8. Disconnect the FTP sensor 3P connector.
  9. Turn the ignition switch ON (II).
  10. Measure voltage between FTP 3P connector terminals No. 1 and No. 2. Is there about 5 V? YES - Go to step 11. NO - Repair open in the wire between the FTP sensor and the ECM/PCM (E4).
  11. Measure voltage between FTP sensor 3P connector terminals No. 2 and No. 3. Is there about 5 V? YES - Replace the FTP sensor. NO - Go to step 12.
  12. Measure voltage between ECM/PCM connector terminals E4 and E14. Is there about 5 V? YES - Repair open in the wire between the FTP sensor and the ECM/PCM (E14) NO - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck (see «ECM/PCM UPDATING AND SUBSTITUTION FOR TESTING»(ref-171385-S32387647222005020300000) ). If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM.

Special Tools Required

Vacuum pump/gauge, 0-30 in.Hg A973X-041-XXXXX

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Scheme 37: DTC P0497: EVAP System Low Purge Flow
Scheme 37: DTC P0497: EVAP System Low Purge Flow

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Scheme 50
  1. Turn the ignition switch ON (II).
  2. Measure voltage between ECM/PCM connector terminal B21 and body ground. Is there battery voltage? YES - Go to step 3. NO - Go to step 8 .
  3. Turn the ignition switch OFF.
  4. Disconnect the vacuum hose (A) from the EVAP canister purge valve (B) and connect a vacuum pump/gauge to the hose.
  5. Connect the ECM/PCM connector terminal B21 to body ground with a jumper wire.
  6. Turn the ignition switch ON (II).
  7. Apply vacuum to the hose. Does the valve hold vacuum? YES - Replace the EVAP canister purge valve (see «THROTTLE BODY DISASSEMBLY/REASSEMBLY»(ref-171389-S03058078252005020300000) ). NO - Go to step 16 .
  8. Turn the ignition switch OFF.
  9. Disconnect the ECM connector B (24P).
  10. Connect the ECM/PCM connector terminal B21 to body ground with a jumper wire.
  11. Disconnect the EVAP canister purge valve 2P connector.
  12. Check for continuity between the EVAP canister purge valve 2P connector terminal No. 2 and body ground. Is there continuity? YES - Go to step 13. NO - Repair open in the wire between the EVAP canister purge valve and the ECM/PCM (B21).
  13. Turn the ignition switch ON (II).
  14. Measure voltage between the EVAP canister purge valve 2P connector terminal No. 1 and body ground. Is there battery voltage? YES - Go to step 15. NO - Repair open in the wire between the EVAP canister purge valve and the No. 4 ACG (10A) fuse in the under-dash fuse/relay box.
  15. Measure resistance between the EVAP canister purge valve 2P connector terminals No. 1 and No. 2. Is there about 33 ohm at room temperature? YES - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck (see «ECM/PCM UPDATING AND SUBSTITUTION FOR TESTING»(ref-171385-S32387647222005020300000) ). If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM. NO - Replace the EVAP canister purge valve (see «THROTTLE BODY DISASSEMBLY/REASSEMBLY»(ref-171389-S03058078252005020300000) ).
  16. Measure voltage between ECM/PCM connector terminal E21 and body ground. Is there battery voltage? YES - Go to step 17. NO - Go to step 22 .
  17. Turn the ignition switch OFF.
  18. Disconnect the vacuum hose from the EVAP canister vent filter line (A), and connect a vacuum pump/gauge to the hose.
  19. Connect the ECM/PCM connector terminal E21 to body ground with a jumper wire.
  20. Turn the ignition switch ON (II).
  21. Apply vacuum to the hose. Does the valve hold vacuum? YES - Inspect the vacuum line between the EVAP canister purge valve and the EVAP canister. NO - Replace the EVAP canister vent shut valve (see «THROTTLE BODY DISASSEMBLY/REASSEMBLY»(ref-171389-S03058078252005020300000) ).
  22. Turn the ignition switch OFF.
  23. Disconnect the ECM connector E (31P).
  24. Connect the ECM/PCM connector terminal E21 to body ground with a jumper wire.
  25. Disconnect the EVAP canister vent shut valve 2P connector.
  26. Check for continuity between the EVAP canister vent shut valve 2P connector terminal No. 2 and body ground. Is there continuity? YES - Go to step 27. NO - Repair open in the wire between the EVAP canister vent shut valve and the ECM/PCM (E21).
  27. Turn the ignition switch ON (II).
  28. Measure voltage between the EVAP canister vent shut valve 2P connector terminal No. 1 and body ground. Is there battery voltage? YES - Go to step 29. NO - Repair open in the wire between the EVAP canister vent shut valve and the No. 4 ACG (10A) fuse in the under-dash fuse/relay box.
  29. Measure resistance between the EVAP canister vent shut valve 2P connector terminals No. 1 and No. 2. Is there about 33 ohm at room temperature? YES - Update the ECM/PCM if it does not have the latest software, or substitute a known-good ECM/PCM, then recheck (see «ECM/PCM UPDATING AND SUBSTITUTION FOR TESTING»(ref-171385-S32387647222005020300000) ). If the symptom/indication goes away with a known-good ECM/PCM, replace the original ECM/PCM. NO - Replace the EVAP canister vent shut valve (see step 22 . on ).

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