For 1990-2009 cars
Engine Controls Components
Fuel Injectors
OBD II Symbol Description Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

The PCM controls the fuel injectors by using an ignition feed driver and ground circuit within the PCM. The driver has the ability to detect an electrical malfunction in the ignition feed or ground circuit. If an electrical malfunction occurs in the fuel injector circuit for engine cylinder #4, the ignition feed driver signals the PCM to set DTC P0204.

### Conditions for Running the DTC

The engine is running.

### Conditions for Setting the DTC

• | The PCM detects an electrical malfunction on the injector circuit for engine cylinder #4 for longer than 30 seconds.

• | The condition is present for at least 30 seconds.

### Action Taken When the DTC Sets

• | The PCM will illuminate the malfunction indicator lamp (MIL) during the second consecutive trip in which the diagnostic test has been run and failed.

• | The PCM will store conditions which were present when the DTC set as Freeze Frame and Failure Records data.

### Conditions for Clearing the MIL/DTC

• | The PCM will turn OFF the MIL during the third consecutive trip in which the diagnostic has been run and passed.

• | The History DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

• | The DTC can be cleared by using the scan tool.

### Diagnostic Aids

The misfire history counter may be useful in determining which injector circuit is malfunctioning. If DTC P0300 was set, look at the Misfire Hist # display for each cylinder. The largest value stored in the misfire history counters will indicate the location of the malfunctioning injector circuit or injector.

Check for the following conditions:

• | Poor connection at the PCM or fuel injector.

| Inspect 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.

Reviewing the Freeze Frame/Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

### Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

1. Tests for malfunctioning fuel injector control circuit or ignition feed wiring.

2. Tests for a malfunction in the fuel injector ignition feed circuit.

3. tests for a short to ground in the injector control circuit.

4. Tests for an open in the fuel injector control circuit.

5. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM isreplaced, the new PCM must be programmed.

#### Injector Control Circuit

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to Step 2 | Go to Powertrain On Board Diagnostic (OBD) System Check
2 | With a scan tool and the engine idling, observe Specific DTC info for this DTC. Does the scan tool indicate this DTC failed this ignition? | -- | Go to Step 4 | Go to Step 3
3 |

1. Turn ON the ignition, with the engine OFF.
2. With a scan tool, review and record Fail Records.
3. Operate vehicle within Fail Records conditions.

Does the scan tool indicate this DTC failed this ignition?

--

Go to Step 4

Go to Diagnostic Aids

4 |

1. Turn OFF the ignition.
2. Disconnect the PCM.
3. Turn ON the ignition.
4. Measure the voltage of the fuel injector control circuit at the PCM connector using a J 39200 Digital Multimeter that is connected to a good ground.

Does the voltage measure at or near the specified value?

B+

Go to Step 5

Go to Step 9

5 | Test the fuel injectors. Refer to Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Between 10-35 Degrees C (50-95 Degrees F) or Fuel Injector Solenoid Coil Test - Engine Coolant Temperature Outside 10-35 Degrees C (50-95 Degrees F) .

Are all injectors OK?

--

Go to Step 6

Go to Step 17

6 |

1. Turn OFF the ignition.
2. Disconnect the fuel injector.
3. Turn ON the ignition.
4. Measure the voltage between the fuel injector control circuit at the PCM connector using a DMM that is connected to a good ground.

Does the voltage measure at or near the specified value?

0V

Go to Step 7

Go to Step 16

7 | Test for the following conditions:

1. The injector ignition feed circuit for an intermittent open.
2. The injector control circuit for an intermittent open or short to ground.

Refer to Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 19

Go to Step 8

8 |

1. Inspect for the following conditions:
2. Poor connections at the fuel injector.
3. The injector control circuit for poor connections at the PCM.
4. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 19

Go to Step 18

9 |

1. Turn OFF the ignition.
2. Disconnect the fuel injector.
3. Turn ON the ignition.
4. Measure the voltage on the injector ignition feed circuit using a DMM that is connected to a good ground.

Does the voltage measure at or near the specified value?

B+

Go to Step 10

Go to Step 14

10 | Probe the injector control circuit using a J 35616-200 Test Lamp that is connected to B+. Does the test lamp illuminate? | -- | Go to Step 15 | Go to Step 11
11 |

1. Turn OFF the ignition.
2. Install a fused jumper between the injector control circuit and the ignition feed circuit.
3. Turn ON the ignition.
4. Probe the injector control circuit at the PCM connector with a test lamp that is connected to a good ground.

Does the test lamp illuminate?

--

Go to Step 12

Go to Step 13

12 | Inspect for poor connections at the injector. Refer to Intermittents and Poor Connections Diagnosis and Connector Repairs . Did you find and correct the condition? | -- | Go to Step 19 | Go to Step 17
13 | Locate and repair open in the injector control circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 19 | --
14 | Locate and repair open in the injector ignition feed circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 19 | --
15 | Locate and repair short to ground in the injector control circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 19 | --
16 | Locate and repair short to voltage in the injector control circuit. Refer to Wiring Repairs . Did you complete the repair? | -- | Go to Step 19 | --
17 | Replace malfunctioning fuel injector(s). Refer to Fuel Injector Replacement . Did you complete the replacement? | -- | Go to Step 19 | --
18 | Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming . Replace the PCM. Did you complete the replacement? | -- | Go to Step 19 | --
19 |

1. Use the scan tool in order to clear DTCs.
2. Operate the vehicle within the Fail Record conditions.

Does the DTC reset?

--

Go to Step 2

System OK