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Home >> Isuzu >> 2004 >> Axiom Base, RWD >> Repair and Diagnosis >> Engine Performance >> System >> Engine DRIVEABILITY And Emissions - DTC P1237 To DTC U2104 >> DTC P1239: High Fuel Pressure System >> Test Description

Test Description

  1. Refer to HIGH FUEL PRESSURE SYSTEM  section.
DTC P1239 - HIGH FUEL PRESSURE SYSTEM

Step Action Values Yes No
1 Was the "On-Board Diagnostic (OBDII) System Check" performed? - Go to Step 2 Go to On-Board Diagnostic (OBD-II) System Check
2
  1. Check the fuel quantity.
  2. Check the fuel quality.
  3. Check the fuel filter.
  4. If a problem is found, repair as necessary.
Is the action complete?		 - Go to Step 3 -
3
  1. Check the fuel leakage.
  2. If a problem is found, repair as necessary.
Is the action complete?		 - Go to Step 4 -
4
  1. Check a problem of fuel pipe line.
  2. If a problem is found, repair as necessary.
Is the action complete?		 - Go to Step 5 -
5 Check a power supply circuit of Engine Control Module (ECM).
  1. Turn the ignition "OFF".
  2. Disconnect the connector from ECM.
  3. Operate the key switch.
  4. Measure the voltage between ECM harness connector (K42) and ground.

Is the voltage the specified value?		 K42-GND: (Key "OFF") 0V (Key "On"): Battery voltage Go to Step 7 Go to Step 6
6
  1. Repair the ECM power supply circuit.
  2. Check the battery voltage and specific gravity.
  3. If a problem is found, repair as necessary.
Is the action complete?		 - Go to Step 7 -
7 Check the ECM ground circuit.
  1. Turn the ignition "OFF".
  2. Measure the resistance between ECM harness connector (K1/K2/K4) and ground
  3. Turn the ignition "ON".
  4. Measure the voltage between ECM harness connector (K1/K2/K4) and ground.

Is the voltage and resistance specified value?		 K1/K2/K4 - GND: 0Ω K1/K2/K4 - GND: 0V Go to Step 9 Go to Step 8
8 Repair the ECM ground circuit.
Is the action complete?		 - Go to Step 9 -
9 Check the ECM main relay.
  1. Turn the ignition "OFF".
  2. Connect a jumper wire between ECM harness connector (K49) and ground.
  3. Operate the key switch.
  4. Measure the voltage between ECM harness connector (K3/K5/K64) and ground.

Is the voltage specified value?		 K1/K2/K64 - GND: (Key "OFF") 0V K1/K2/K64 - (Key "ON"): Battery voltage Go to Step 11 Go to Step 10
10
  1. Repair the ECM main relay circuit.
  2. Check the main relay operation.
  3. If a problem is found, repair as necessary.
Is the action complete?		 - Go to Step 11 -
11 Check the DTC.
  1. Turn the ignition "OFF".
  2. Connect all circuit.
  3. Turn the ignition "ON".
  4. Using the scan tool, check the DTC. If a DTC is detected, repair as necessary.

Is the action complete?		 - Go to Step 12 -
12 Check the timing belt.
  1. Turn the ignition "OFF".
  2. Check a problem in a timing belt.
  3. Check a problem in an auto tensioner and a pulley
  4. If a problem is found, repair as necessary.

Is the action complete?		 - Go to Step 13 -
13 Check the engine mechanical timing.
  1. Turn the ignition "OFF".
  2. Check a problem of a timing gap, poor attachment, breakage, etc.
  3. If a problem is found, repair as necessary.

Is the action complete?		 - Go to Step 14 -
14 Check the fuel low pressure line. Refer to Fuel System Check (Low Pressure Line) . Is the action complete? - Go to Step 15
15 Check the fuel high pressure line.
  1. Turn the ignition "OFF".
  2. Connect the scan tool.
  3. Start the engine.
  4. Using the scan tool, check the fuel pressure.
  5. Check the actual fuel pressure does follow desired fuel pressure.

Does the actual fuel pressure follow desired fuel pressure?		 - Go to Step 17 Go to Step 16
16 Check the fuel pump and fuel pressure sensor circuit.
  1. Turn the ignition "OFF".
  2. Check the open circuit, short circuit, and poor connection.
  3. Measure the resistance of fuel pump.
  4. If a problem is found, repair as necessary.

Is the action complete?		 High pressure regulator 8.7+/-10% (about 20 ° C) Go to Step 17 -
17 Check the fuel pressure (high pressure), and check the fuel pump (high pressure) operation.
  1. Turn the ignition "OFF".
  2. Connect the scan tool.
  3. Start the engine.
  4. Using the scan tool, operate the high pressure regulator valve test.
  5. Check the actual fuel pressure does follow desired fuel pressure.

Does the actual fuel pressure follow desired fuel pressure?		 - Verify repair Go to Step 18
18 Check the injector.
  1. Turn the ignition "OFF".
  2. Connect the scan tool.
  3. Start the engine.
  4. Using the scan tool, operate the injector balance test.

Is the injector balance test normal?		 - Go to Step 20 Go to Step 19
19
  1. Check the abnormal injectors, repair as necessary.
Is the action complete.		 - Go to Step 20 -
20 Check the fuel line (high pressure), and check the fuel pump (high pressure).
  1. Check a problem of fuel pipe line.
  2. Check attachment of fuel pump (high pressure).
  3. Check the fuel supply from fuel pump (high pressure) to fuel rail.
  4. Check a specific of fuel pressure sensor.
  5. If a problem is found, repair as necessary.

Is the action complete.		 - Go to Step 21 -
21 Recheck the fuel line (high pressure), and recheck the fuel pump (high pressure) operation.
  1. Turn the ignition "OFF".
  2. Connect the scan tool.
  3. Start the engine.
  4. Using the scan tool, operate the high pressure regulator valve test.
  5. Check the actual fuel pressure does follow desired fuel pressure.

Does the actual fuel pressure follow desired fuel pressure?		 - Verify repair Go to Step 22
22
  1. Ignition "ON", reprogram The EEPROM. Refer to EEPROM .
  2. Using the Tech 2 output controls function, select MIL dash lamp control and command the MIL "OFF".
 Did the MIL turn "OFF"?		 - Go to On-Board Diagnostic (OBD-II) System Check Go to Step 23
23 Is the ECM programmed with the latest software release?
If not, download the latest software to the ECM using the "SPS (Service Programming System)".
Was the problem solved?		 - Verify repair Go to Step 24
26 Install the test ECM.
Program the test ECM (Immobilizer system). Refer to IMMOBILIZER SYSTEM .
Check the OBD-II test for following condition:
  1. When the ignition is "ON", turn on the MIL and RPL (RPL is put out after 3 seconds).
  2. When the engine is started.

Did the DTC disappear?		 - Go to Step 25 Go to Step 2
27 Replace the original ECM.
Check the poor connection between the ECM and ECM connector.
Recheck the OBD-II test again.
When the engine is started.
Did the DTC disappear?		 - Verify repair Go to Step 26
28 Disconnect the ABS control unit connector.
Reprogramming the original ECM. (Engine control and Immobilizer control)
Recheck the OBD-II.
Did the DTC disappear?		 - Verify repair Go to Step 27
29 Replace the ECM.
Recheck the OBD-II test again.
Did the DTC disappear?		 - Verify repair Refer to Diagnostic Aids
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