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DTC P0088: Fuel System Pressure Too High
 
 
 
 
CIRCUIT OPERATION
Refer to DTC P0192 - Fuel Pressure Circuit Low Input , DTC P0628 - Fuel Pump (high pressure) Control Circuit Low .
 
 
TECHNICAL DESCRIPTION
  • The ECM monitors the signals input from the fuel rail pressure sensor.
  • Based on the input signals, the ECM checks whether the fuel rail pressure exceeds the maximum pressure of the system.
 
 
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)
  • Fuel pump (high pressure) monitor
Sensor (The sensor below is determined to be normal)
  • Fuel rail pressure sensor
 
 
DTC SET CONDITIONS
Logic Flow Chart
 
 
Check Conditions
  • More than 3 seconds have passed since the engine starting sequence was completed.
  • Battery positive voltage is higher than 10 volts.
  • Fuel injection mode is not MFI-mode.
  • The estimated fuel rail pressure subtracted from the fuel rail pressure sensor output equals 0 kPa (0 in.Hg) or higher.
Judgment Criteria
  • For 2 seconds, the estimated fuel rail pressure subtracted from the fuel rail pressure sensor output equals higher than the specified value.
noteStop the monitor within 3 seconds of starting the DFI and MFI mode, or stop the monitor within 10 seconds of exceeding the fuel rail pressure of 20,000 kPa (5,906.7 in.Hg) in the DFI and MFI mode.
 
 
DTC SET CONDITIONS
Logic Flow Chart
 
 
Check Conditions
  • After 2 seconds since the ignition switch is turned ON or since the completion of engine start.
  • Battery positive voltage is higher than 6 volts.
Judgment Criteria
  • The fuel rail pressure is the specified value or higher.
 
 
FAIL-SAFE AND BACKUP FUNCTION
  • While prohibiting the operation of the injector (high pressure), carry out the control by the injector operation only.
  • Torque is restricted.
 
 
OBD-II DRIVE CYCLE PATTERN
  • Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1 .
 
 
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
  • Fuel pump (high pressure) circuit harness damage, or connector damage.
  • Fuel pump (high pressure) failed.
  • Injector (high pressure) failed.
  • Fuel rail pressure sensor failed.
  • ECM failed.

 
 
DIAGNOSIS
STEP 1. Using scan tool (M.U.T.-IIISE), read the diagnostic trouble code (DTC).
cautionTo prevent damage to scan tool (M.U.T.-IIISE), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool (M.U.T.-IIISE).
(1) Connect scan tool (M.U.T.-IIISE) to the data link connector.
(2) Turn the ignition switch to the "ON" position.
(3) Set scan tool (M.U.T.-IIISE), read the DTC.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Is the diagnostic trouble code other than P0088 set?
Refer to Diagnostic Trouble Code Chart .
Go to Step 2.
 
STEP 2. Check of short circuit and harness damage in HFP+ line between fuel pump (high pressure) connector and ECM connector.
Is the harness wire in good condition?
Go to Step 3.
Repair the connector(s) or wiring harness. Then go to Step 7.
 
STEP 3. Check of short circuit and harness damage in HFP- line between fuel pump (high pressure) connector and ECM connector.
Is the harness wire in good condition?
Go to Step 4.
Repair the connector(s) or wiring harness. Then go to Step 7.
 
STEP 4. Check the injector (high pressure).
Refer to Injector (high pressure) check .
Is the measured resistance normal?
Go to Step 5.
Replace the faulty injector (high pressure). Then go to Step 7.
 
STEP 5. Check the trouble symptoms.
(1) Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1 .
(2) Check the diagnostic trouble code (DTC).
Is DTC P0088 set?
Go to Step 6.
It can be assumed that this malfunction is intermittent. Refer to GROUP 00, How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions .
 
STEP 6. Replace the fuel pump (high pressure).
(1) Replace the fuel pump (high pressure).
(2) Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1 .
(3) Check the diagnostic trouble code (DTC).
Is DTC P0088 set?
Replace the ECM (Refer to Removal and Installation ). Then go to Step 7.
The inspection is complete.
 
STEP 7. Test the OBD-II drive cycle.
(1) Carry out a test drive with the drive cycle pattern. Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 1 .
(2) Check the diagnostic trouble code (DTC).
Is DTC P0088 set?
Retry the troubleshooting.
The inspection is complete.