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Home >> Mazda >> 2006 >> B4000 Base, Automatic >> Repair and Diagnosis >> Engine Performance >> Testing & Diagnosis >> Engine Symptom Troubleshooting - (3 Of 5) >> DTC Application Chart - Powertrain Control Module (Pcm) >> Canister Vent (CV) Solenoid Malfunction

Canister Vent (CV) Solenoid Malfunction

DTC P1451 DETECTION CONDITION & POSSIBLE CAUSES

DTC P1451 CANISTER VENT (CV) SOLENOID MALFUNCTION
DETECTION CONDITION 
  • P1451 indicates the self-test has detected a canister vent (CV) solenoid circuit failure.
POSSIBLE CAUSE 
  • VPWR circuit open
  • CV circuit open CV circuit shorted to PWR GND or CHASSIS GND
  • CV circuit shorted to VPWR
  • Damaged CV solenoid
  • Damaged powertrain control module (PCM)
HINT  CV Solenoid Description 
  • Seals the evaporative emission (EVAP) canister from atmospheric pressure during the EVAP test monitor. This allows the EVAP canister purge valve to obtain the target vacuum in the fuel tank during the monitor run.
G04306981Courtesy of MAZDA MOTORS CORP.
DTC P1451 DIAGNOSTIC PROCEDURE

DTC P1451 CANISTER VENT (CV) SOLENOID MALFUNCTION
STEP INSPECTION ACTION
1
  • Was the PCM quick test performed?
 Yes Go to next step.
No Perform PCM quick test. See PCM QUICK TEST  .
2 DTC P1451: CHECK VPWR VOLTAGE TO CANISTER VENT SOLENOID
  • Key OFF.
  • Disconnect CV solenoid.
  • Connect a non-powered test lamp between CV and VPWR circuits at the CV solenoid harness connector.
  • Key on, engine off (KOEO).
  • Using WDS or equivalent tester, select Diagnostic Data Link.
  • Select PCM.
  • Select PID/Data Monitor and Record.
  • Attempt to close and open CV solenoid driver in PCM by accessing output test mode.
  • Select ALL OFF mode.
  • Cycle START button ON and OFF, and observe the test lamp.
  • Does the test lamp cycle on and off (light up and turn off)? 
 Yes Key OFF.
Go to next step.
No For test light always off:
Go to step 4.
For test light always on:
Key OFF.
Go to step 8.
3 CHECK CV SOLENOID RESISTANCE
  • Measure CV solenoid resistance.
  • Is resistance between 45 and 65 ohms? 
 Yes Unable to identify fault at this time.
See GENERAL PINPOINT TEST 4: INTERMITTENT .
No Replace damaged CV solenoid.
See CANISTER VENT SOLENOID REMOVAL / INSTALLATION .
4 CHECK FOR OPEN VPWR CIRCUIT BETWEEN CV SOLENOID AND POWER RELAY
  • Measure voltage of VPWR circuit between the CV solenoid harness connector and battery negative post.
  • Is voltage greater than 10.5 V? 
 Yes Key OFF.
Go to next step.
No Key OFF.
Repair open circuit.
Go to step 10.
5 CHECK VPWR CIRCUIT FOR OPENING IN HARNESS
  • Disconnect PCM.
  • Install breakout box, leave PCM disconnected.
  • Measure resistance of VPWR circuit between PCM test pin 71 and CV solenoid harness connector.
  • Is resistance less than 5.0 ohms? 
 Yes Go to next step.
No Repair open circuit.
Go to step 10.
6 CHECK CV CIRCUIT FOR OPEN IN HARNESS
  • Measure resistance of CV circuit between PCM test pin 67 and CV solenoid harness connector.
  • Is resistance less than 5.0 ohms? 
 Yes Replace PCM.
See POWERTRAIN CONTROL MODULE (PCM) REMOVAL / INSTALLATION .
Go to next step.
No Repair open circuit.
Go to step 10.
7 CHECK CV CIRCUIT FOR SHORT TO VPWR
  • Key on, engine off (KOEO).
  • Measure voltage of CV circuit between CV solenoid harness connector and chassis ground.
  • Is voltage less than 1.0 V? 
 Yes Replace PCM.
See POWERTRAIN CONTROL MODULE (PCM) REMOVAL / INSTALLATION .
Go to step 10.
No Repair short to VPWR.
Go to step 10.
8 CHECK CV CIRCUIT FOR SHORT TO PWR GND IN HARNESS
  • Disconnect PCM.
  • Disconnect WDS or equivalent tester.
  • Measure resistance of CV circuit between CV solenoid harness connector and battery negative post.
  • Is resistance greater than 10K ohms? 
 Yes Go to next step.
No Repair short circuit.
Go to step 10.
9 CHECK CIRCUIT FOR SHORT TO POWER
  • Reconnect PCM.
  • Key on, engine off (KOEO).
  • Measure voltage between CV solenoid harness and battery negative ground.
  • Key OFF.
  • Is voltage less than 1.0 V? 
 Yes Replace PCM.
See POWERTRAIN CONTROL MODULE (PCM) REMOVAL / INSTALLATION .
Go to next step.
No Repair short circuit to VPWR, VREF or chassis ground.
Go to next step.
10 VERIFY TROUBLESHOOTING OF DTCs COMPLETED
  • Connect all disconnected connectors.
  • Clear DTCs from PCM memory using WDS or equivalent tester.
  • Perform PCM quick test.
  • Is same DTC present? 
 Yes Replace PCM.
See POWERTRAIN CONTROL MODULE (PCM) REMOVAL / INSTALLATION .
Repeat PCM quick test.
No If any other DTC is present, go to applicable DTC inspection. See DIAGNOSTIC TROUBLE CODE (DTC) INDEX - POWERTRAIN CONTROL MODULE (PCM) . If no DTC is present, troubleshooting is complete.
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