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DTC P1446-12: EVAP System Bypass Solenoid Valve Circuit High
 
 
 
 
CIRCUIT OPERATION
  • Bypass valve is built into the evaporative emission canister (main).
  • MFI relay is built into the IPDM E/R.
  • The bypass valve power is supplied from the MFI relay.
  • The ECM controls bypass valve by turning the power transistor in the ECM "ON" and "OFF".
 
 
TECHNICAL DESCRIPTION
In response to a signal from the ECM, the bypass valve shuts off or opens the path between the purge line and the evaporative emission canister.
 
 
MONITOR EXECUTION
Continuous.
 
 
MONITOR EXECUTION CONDITIONS (Other monitor and Sensor)
Other Monitor (There is no temporary DTC set in memory for the item monitored below)
  • Not applicable
Sensor (The sensor below is determined to be normal)
  • Not applicable
 
 
DTC SET CONDITIONS
Logic Flow Chart
Check Conditions
  • Power supply mode of electric motor switch is ON.
  • 12V battery positive voltage is between 10.0 and 16.5 volts.
Judgment Criterion
  • The coil current is 2.3 amperes or higher with the bypass valve driving for 2 seconds.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • Prohibit introduction of purges.
  • Fuel filler lid cannot be opened even when pressing the fuel filler opener switch.
  • Indicates "REFUELING SYSTEM SERVICE REQUIRED" on the information screen in the multi-information display.
 
 
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 1 OBD- II DRIVE CYCLE.
 
 
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
  • Bypass valve [built into the evaporative emission canister (main)] failed.
  • Shorted bypass valve circuit, harness damage or connector damage.
  • ECM failed.
 
 
DIAGNOSIS
Required Special Tools:
  • MB992744: Vehicle communication interface-Lite (V.C.I.-Lite)
  • MB992745: V.C.I.-Lite main harness A
  • MB992747: V.C.I.-Lite USB cable short
  • MB992748: V.C.I.-Lite USB cable long
1.STEP 1. Using scan tool (M.U.T.-IIISE), perform the actuator test.
Use scan tool (M.U.T.-III SE) to perform the actuator test (Refer to ACTUATOR TEST REFERENCE TABLE).
  • Item number 80: EVAP System Bypass Solenoid Valve
OK: You can hear the operation sound when driving
Q: Is the check result normal?
 
2.STEP 2. Check harness between bypass valve connector terminal number 1 and ECM connector terminal number 66.
Check output line for short circuit to power supply.
Q: Is the check result normal?
Replace the evaporative emission canister (main) (integrated with bypass valve) (Refer to ENGINE, Engine, Motor and Emission Control – Emission Control – Evaporative Emission System FUEL TANK SOLENOID VALVE REPLACEMENT). Then
Repair or replace the connector, or repair the damaged harness wire.
 
3.STEP 3. Using scan tool (M.U.T.-IIISE), perform the actuator test.
Use scan tool (M.U.T.-III SE) to perform the actuator test (Refer to ACTUATOR TEST REFERENCE TABLE).
  • Item number 80: EVAP System Bypass Solenoid Valve
OK: You can hear the operation sound when driving
Q: Is the check result normal?
Replace the ECM (Refer to ENGINE CONTROL MODULE (ECM) REMOVAL AND INSTALLATION).
 
4.STEP 4. Test the OBD-II drive cycle.
After erasing the DTC, carry out test drive with the drive cycle pattern, and recheck the DTC.
(1) Use scan tool (M.U.T.-III SE) to erase the DTC.
(2) Carry out test drive with the drive cycle pattern (Refer to Diagnostic Function, OBD-II Drive Cycle – Pattern 1 OBD- II DRIVE CYCLE).
(3) Use scan tool (M.U.T.-III SE) to recheck the DTC.
Q: Is DTC P1446-12 set?
Replace the ECM (Refer to ENGINE CONTROL MODULE (ECM) REMOVAL AND INSTALLATION).
Intermittent malfunction (Refer to GENERAL INFORMATION, General Information – How to Use Troubleshooting/Inspection Service Points – How to Cope with Intermittent Malfunctions HOW TO COPE WITH INTERMITTENT MALFUNCTIONS).