DTC P0451: FTP Sensor Range/Performance Problem Honda Civic VII рестайлинг

Special Tools Required

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

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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 a scan tool, or measure voltage between ECM connector terminals E4 and E14. Is there about 2.5V? 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 a scan tool, or measure voltage between ECM connector terminals E4 and E14, and carefully squeeze the vacuum pump a little.
9. The voltage should smoothly drop from about 2.5 V 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 misrouted, leaking, or broken FTP sensor vacuum lines. If the vacuum lines are OK, update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck (see «ECM UPDATING AND SUBSTITUTION FOR TESTING»(ref-171994-S19233909092005021700000) ). If the symptom/indication goes away with a known-good ECM, replace the original ECM. NO: Replace the FTP sensor.

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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 (see «HOW TO RESET THE ECM»(ref-171994-S27513286122005021700000) ).
3. Remove the fuel fill cap.
4. Turn the ignition switch ON (II).
5. Monitor FTP sensor voltage with the HDS or a scan tool, or measure voltage between body ground and ECM 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. 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 (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 connector E (31P).
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 (E14). NO: Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck (see «ECM UPDATING AND SUBSTITUTION FOR TESTING»(ref-171994-S19233909092005021700000) ). If the symptom/indication goes away with a known-good ECM, replace the original ECM.

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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 (see «HOW TO RESET THE ECM»(ref-171994-S27513286122005021700000) ).
3. Remove the fuel fill cap.
4. Turn the ignition switch ON (II).
5. Monitor FTP sensor voltage with the HDS or a scan tool, or measure voltage between body ground and ECM 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. 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 (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 connector terminals E4 and E14. Is there about 5 V? YES: Repair open in the wire between the FTP sensor and the ECM (E14). NO: Update the ECM if it does not have the latest software, or substitute a known-good ECM, then recheck (see «ECM UPDATING AND SUBSTITUTION FOR TESTING»(ref-171994-S19233909092005021700000) ). If the symptom/indication goes away with a known-good ECM, replace the original ECM.

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1. Turn the ignition switch ON (II).
2. Measure voltage between ECM 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 commercially available vacuum pump/gauge, 0-3 in. HG (A973X-041-XXXXX or Snap-On YA4000A or equivalent) to the hose.
5. Connect the ECM 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-172063-S23579340702005021800000) ). NO: Go to step 16 .
8. Turn the ignition switch OFF.
9. Disconnect the ECM connector B (24P).
10. Connect the ECM 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 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 the ECM (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 if it does not have the latest software, or substitute a known-good ECM, then recheck (see «ECM UPDATING AND SUBSTITUTION FOR TESTING»(ref-171994-S19233909092005021700000) ). If the symptom/indication goes away with a known-good ECM, replace the original ECM. NO: Replace the EVAP canister purge valve (see «THROTTLE BODY DISASSEMBLY/REASSEMBLY»(ref-172063-S23579340702005021800000) ).
16. Measure voltage between ECM 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 commercially available vacuum pump/gauge, 0-3 in. Hg (A0973X-041-XXXXX
19. Connect the ECM 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.
22. Turn the ignition switch OFF.
23. Disconnect the ECM connector E (31P).
24. Connect the ECM 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 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 (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 if it does not have the latest software, or substitute a known-good ECM, then recheck (see «ECM UPDATING AND SUBSTITUTION FOR TESTING»(ref-171994-S19233909092005021700000) ). If the symptom/indication goes away with a known-good ECM, replace the original ECM. NO: Replace the EVAP canister vent shut valve.