DTC P0088 Without RPO CTF
Circuit Description
The common rail is installed on the intake manifold, and is equipped with a flow damper, pressure limiter, and common rail pressure sensor.
The common rail unit has a common fuel passage and fuel passage holes. The common rail pressure sensor is installed at the left end of the unit.
The engine control module (ECM) monitors the common rail pressure signals for voltage outside the normal range of 10-104 kPa (1.5-15 psi) of the rail pressure sensor. If the ECM detects a common rail pressure signal voltage that is excessively low, this DTC will set.
Conditions for Running the DTC
| • | The battery voltage is more than 8 volts. |
| • | The fuel injection pump speed is more than 450 RPM. |
| • | The coolant temperature is 60°C (140°F) or more. |
| • | DTC P0190, P0192, or P0193 is not set. |
Conditions for Setting the DTC
Common rail pressure is more than 10 MPa (1,450 psi) over the target pressure.
Action Taken When the DTC Sets
| • | The control module illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that the diagnostic runs and fails. |
| • | The ECM limits fuel delivery. |
Conditions for Clearing the MIL/DTC
| • | The control module turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | A history DTC clears after 40 consecutive warm-up cycles, if no failures are reported by this or any other emission related diagnostic. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
Inspect for the following conditions:
| • | Poor connection at the ECM |
| Inspect the harness connectors for backed-out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal-to-wire connection. |
| • | Damaged harness |
| Inspect the wiring harness for damage, shorts to ground, shorts to battery, and open circuits. If the harness appears to be OK, observe the Rail Pressure display on the scan tool while moving connectors and wiring harnesses related to the common rail pressure sensor. A change in the common rail pressure scan tool display will indicate the location of the fault. |
Step | Action | Value | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||||||||
1 | Does the DTC set while the engine is running? | -- | Go to Step 2 | Go to Diagnostic Aids | ||||||
2 |
Does the voltage measure more than the specified value? | 1.4 V | Go to Step 6 | Go to Step 3 | ||||||
3 |
Does the DTC reset? | -- | Go to Step 5 | Go to Step 4 | ||||||
4 | Inspect for a poor connection at the rail pressure sensor harness connector. Is the connection good? | -- | System OK | Go to Step 9 | ||||||
5 |
Did you find and correct the condition? | -- | Go to Step 16 | Go to Step 7 | ||||||
6 |
Does each resistance measure less than the specified value? | 2 ohms | Go to Step 7 | Go to Step 10 | ||||||
7 | Measure the resistance of the following circuits to ground:
Does each resistance measure more than the specified value? | 10 M ohms | Go to Step 8 | Go to Step 11 | ||||||
8 |
Does the DTC reset? | -- | Go to Step 13 | Go to Step 12 | ||||||
9 | Repair the rail pressure sensor wiring harness. Did you complete the repair? | -- | Go to Step 14 | -- | ||||||
10 | Repair/replace or correct connections of the rail pressure sensor harness connector. Did you complete the action? | -- | Go to Step 14 | -- | ||||||
11 | Repair the rail pressure sensor harness short to ground. Did you complete the repair? | -- | Go to Step 14 | -- | ||||||
12 | Replace the rail pressure sensor harness. Did you complete the replacement? | -- | Go to Step 14 | -- | ||||||
13 | Replace the rail pressure sensor. Did you complete the replacement? | -- | Go to Step 14 | -- | ||||||
14 | Clear all DTCs then operate the vehicle within the conditions to run the DTC. Does the DTC reset? | -- | Go to Step 15 | Go to Step 17 | ||||||
15 | Replace the ECM. Did you complete the replacement? | -- | Go to Step 16 | -- | ||||||
16 | Clear all DTCs then operate the vehicle within the conditions to run the DTC. Does the DTC reset? | -- | Go to Step 2 | Go to Step 17 | ||||||
17 | Do any other DTCs set? | -- | System OK | |||||||
DTC P0088 With RPO CTF
Circuit Description
The engine control module (ECM) monitors fuel rail pressure (FRP) using the FRP sensor. If the sensor indicates a pressure more than the commanded rail pressure, plus a possible transitional overshoot, the ECM will set DTC P0088 for fuel rail pressure too high.
Conditions for Running the DTC
| • | The engine coolant temperature (ECT) is between 30-100°C (86-212°F). |
| • | The fuel temperature is between 20-80°C (68-176°F). |
| • | The deviation of rail pressure is less than 5 MPa (725 psi). |
| • | The deviation of engine speed is less than 50 RPM. |
| • | The above conditions are met for 5 seconds. |
| • | The engine is running. |
| • | The battery voltage is between 10-16 volts. |
Conditions for Setting the DTC
| • | Commanded fuel supply is 0 mm³/stroke. |
| • | Actual fuel rail pressure is higher than desired pressure 1 450 psi (10 MPa). |
| • | The above conditions are met for 22 seconds. |
Action Taken When the DTC Sets
| • | The ECM illuminates the malfunction indicator lamp (MIL) and reduced engine power indicator lamp, if equipped, when the diagnostic runs and fails. |
| • | The ECM records the operating conditions at the time the diagnostic fails. The ECM stores this information in the Failure Records. |
| • | The ECM limits accelerator operating range. |
| • | The ECM limits fuel injection quantity. |
| • | The ECM limits fuel rail pressure. |
| • | The ECM closes the exhaust gas recirculation (EGR) valve and stops EGR control. |
| • | The ECM inhibits cruise control. |
Conditions for Clearing the DTC
| • | The MIL resets when the ignition is turned OFF. |
| • | A current DTC, Last Test Failed, clears when the diagnostic runs and passes. |
| • | Clear the MIL and the DTC with a scan tool. |
Diagnostic Aids
| • | An intermittently sticking suction control valve (SCV) may have allowed the fuel pressure to become high enough to set this DTC. |
| • | Normal actual fuel rail pressure readings on the scan with the engine running Park or Neutral at idle are 3 650-5 050 psi (25-35 MPa) and 8 700-18 850 psi (60-130 MPa) in Park or Neutral at WOT, accelerator pedal full travel. |
| • | A skewed fuel rail pressure (FRP) sensor value, shifted to a higher pressure, can set this DTC. The actual fuel rail pressure on the scan tool should read 0 psi (0 MPa) with the key ON and the engine OFF after the engine has stopped running for a minimum of 2 minutes. |
| • | Resistance in the FRP sensor low reference circuit can set this DTC. Ensure that the sensor low reference circuit has no resistance and the connectors are tight and free of corrosion. |
Step | Action | Values | Yes | No | ||||
|---|---|---|---|---|---|---|---|---|
Schematic Reference: Engine Controls Schematics | ||||||||
1 | Did you perform the Diagnostic System Check - Engine Controls? | -- | Go to Step 2 | |||||
2 |
Did the DTC fail this ignition? | -- | Go to Step 3 | Go to Intermittent Conditions | ||||
3 |
Did the DTC fail this ignition? | -- | Go to Step 13 | Go to Step 4 | ||||
4 |
Was a condition found? | -- | Go to Step 13 | Go to Step 5 | ||||
5 |
Did you find and correct the condition? | -- | Go to Step 10 | Go to Step 6 | ||||
6 |
Is the fuel parameter near the specified value? | 0 MPa | Go to Step 7 | Go to Step 9 | ||||
7 |
Is the parameter within the specified range? | 25-40 MPa (3,626-5,801 psi) | Go to Step 8 | Go to Step 9 | ||||
8 |
Was a condition found? | -- | Go to Step 12 | Go to Step 11 | ||||
9 | Replace the fuel rail assembly. Did you complete the replacement? | -- | Go to Step 13 | -- | ||||
10 | Review the DTC.
Is the DTC current? | -- | Go to Step 11 | Go to Step 13 | ||||
11 | Replace the supply pump assembly. Did you complete the replacement? | -- | Go to Step 13 | -- | ||||
12 |
Important: The new ECM must be programmed. Replace the ECM. Refer to Engine Control Module Replacement/Restore Fuel Rate Data . Did you complete the replacement? | -- | Go to Step 13 | -- | ||||
13 |
Did the DTC fail this ignition? | -- | Go to Step 2 | Go to Step 14 | ||||
14 | Observe the Capture Info with a scan tool. Are there any DTCs that have not been diagnosed? | -- | System OK | |||||
