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DTC P0451: FTP Sensor Range/Performance Problem Honda Accord VI

Auxiliary Emission Control Systems 12 illustrations ~785 words

Special Tools Required

  1. Vacuum Pump/Gauge, 0-30 in. Hg A973X-041-XXXXX

Scheme 42

Scheme 42
Scheme 42

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Scheme 43

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Scheme 44

Scheme 45

Scheme 45
Scheme 45
  1. Remove the fuel fill cap.
  2. Turn the ignition switch ON (II).
  3. Monitor FTP sensor voltage with the Honda PGM Tester, or measure voltage between ECM/PCM connector terminals A29 and C18. Is there approx. 2.5 V? YES - Go to step 4. NO - Replace the FTP sensor.
  4. Turn the ignition switch OFF.
  5. Open the fuel vent assembly cover (A) in front of the EVAP canister.
  6. Disconnect the hose between the EVAP two way valve and the FTP sensor at the EVAP two way valve end.
  7. Connect a vacuum pump to the open end of that hose.
  8. Turn the ignition switch ON (II).
  9. Monitor FTP sensor voltage with the Honda PGM Tester, or measure voltage between PCM connector terminals A29 and C18, and carefully squeeze the vacuum pump slowly.
  10. The voltage should smoothly drop from approx. 2.5 V down to approx. 1.5 V. STOP applying vacuum when the voltage drops to approx. 1.5 V or damage to the FTP sensor may occur. Does the voltage drop to approx. 1.5 V and hold? YES - Check for misrouted, leaking, or broken FTP sensor vacuum lines. If the vacuum lines are OK, substitute a known-good ECM/PCM and recheck (see «HOW TO SUBSTITUTE THE ECM/PCM FOR TESTING PURPOSES»(ref-177983-S06033682252005060900000) ). If the symptom/indication goes away, replace the original ECM/PCM. NO - Replace the FTP sensor.

Scheme 46

Scheme 46: DTC P0452: FTP Sensor Circuit Low Voltage
Scheme 46: DTC P0452: FTP Sensor Circuit Low Voltage

Scheme 47

Scheme 47
Scheme 47

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Scheme 48

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Scheme 49
Scheme 49
  1. Check the vacuum lines of 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-177983-S09317242002005060900000) ).
  3. Remove the fuel fill cap.
  4. Turn the ignition switch ON (II).
  5. Monitor FTP sensor voltage with the Honda PGM Tester, or measure voltage between body ground and ECM/PCM connector terminal A29. Is there approx. 2.5 V? YES - Intermittent failure, system is OK at this time. Check for poor connections or loose wires at the FTP sensor and 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 approx. 5 V? YES - Go to step 11. NO - Repair open in the wire between the FTP sensor and the ECM/PCM (C28).
  11. Measure voltage between FTP sensor 3P connector terminals No. 2 and No. 3. Is there approx. 5 V? YES - Replace the FTP sensor. NO - Go to step 12.
  12. Turn the ignition switch OFF.
  13. Disconnect ECM/PCM connector A (32P).
  14. Check for continuity between FTP sensor 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 (A29). NO - Substitute a known-good ECM/PCM and recheck (see «HOW TO SUBSTITUTE THE ECM/PCM FOR TESTING PURPOSES»(ref-177983-S06033682252005060900000) ). If the symptom/indication goes away, replace the original ECM/PCM.

Scheme 50

Scheme 50: DTC P0453: FTP Sensor Circuit High Voltage
Scheme 50: DTC P0453: FTP Sensor Circuit High Voltage

Scheme 51

Scheme 51
Scheme 51

Scheme 52

Scheme 52
Scheme 52

Scheme 53

Scheme 53
Scheme 53
  1. Check the vacuum lines of 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-177983-S09317242002005060900000) ).
  3. Remove the fuel fill cap.
  4. Turn the ignition switch ON (II).
  5. Monitor FTP sensor voltage with the Honda PGM Tester, or measure voltage between body ground and ECM/PCM connector terminal A29. Is there approx. 2.5 V? YES - Intermittent failure, system is OK at this time. Check for poor connections or loose wires at the FTP sensor and 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 approx. 5 V? YES - Go to step 11. NO - Repair open in the wire between the FTP sensor and the ECM/PCM (C28).
  11. Measure voltage between FTP sensor 3P connector terminals No. 2 and No. 3. Is there approx. 5 V? YES - Replace the FTP sensor. NO - Go to step 12.
  12. Measure voltage between ECM/PCM connector terminals A29 and C18. Is there approx. 5 V? YES - Repair open in the wire between the FTP sensor and ECM/PCM (A29). NO - Substitute a known-good ECM/PCM and recheck (see «HOW TO SUBSTITUTE THE ECM/PCM FOR TESTING PURPOSES»(ref-177983-S06033682252005060900000) ). If the system/indication goes away, replace the original ECM/PCM.

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