P0204

Injector Circuit:

Connector: A-21X, B-01, B-02, B-05, B-06, C-49 <M/T>, C-50 <A/T>:

CIRCUIT OPERATION
- The injector power is supplied from the MFI relay (terminal 1).
- The ECM or PCM controls the injector by turning the power transistor in the ECM or PCM "ON" and "OFF."

TECHNICAL DESCRIPTION
- The amount of fuel injected by the injector is controlled by the amount of time the injector solenoid coil is grounded by the ECM or PCM.
- A surge voltage is generated when the injectors are driven and the current flowing to the injector coil is shut off.
- The ECM or PCM checks this surge voltage.

DTC SET CONDITIONS

Check Conditions
- Engine speed is lower than 1,000 r/min.
- Throttle position sensor output voltage is lower than 1.16 volts.

Judgment Criteria
- Injector coil surge voltage (battery positive voltage + 2 volts) has not been detected for two seconds.

TROUBLESHOOTING HINTS
The most likely causes for this code to be set are:
- Injector failed.
- Open or shorted injector circuit, or loose connector.
- ECM failed.
- PCM failed.

DIAGNOSIS
Required Special Tool:
MB991348: Test Harness Set

STEP 1. Check the injector.
1. Disconnect the injector connector.

2. Measure the resistance between each injector side connector terminals 1 and 2.

Standard value: 13 - 16 ohms [at 20°C (68°F)]

If within specifications, go to Step 2.
If not within specifications, replace the injector. Then go to Step 7.

STEP 2. Check the power supply line at injector connectors B-01, B-02, B-05, B-06.
1. Disconnect connectors B-01, B-02, B-05, B-06 and measure at the harness side.
2. Turn the ignition switch to "ON" position.
3. Measure the voltage between terminal 1 and ground.
- Voltage should approximately l2volts (battery positive voltage).

4. Turn the ignition switch to "LOCK" (OFF) position.
If within specifications, go to Step 3.

If not within specifications, repair the harness wires between MFI relay connector A-21X and injector connectors B-01, B-02, B-05, B-06. Then go to Step 7.

STEP 3. Check harness connectors B-01, B-02, B-05, B-06 at the injector for damage.
If harness connectors B-01, B-02, B-05, B-06 are in good condition, go to Step 4.
If harness connectors B-01, B-02, B-05, B-06 are damaged, repair or replace them.
Refer to Harness Connector Inspection. Then go to Step 7.

STEP 4. Check the circuits at ECM connector C-49 or PCM connector C-50 .
1. Disconnect connector C-49 or C-50 and measure at the harness side.
2. Turn the ignition switch to "ON" position.
3. Measure the voltage between terminal 1, 2, 14, 15 or 1, 2, 9, 24 and ground.
- Voltage should be approximately 12 volts (battery positive voltage).

4. Turn the ignition switch to "LOCK" (OFF) position.
If within specifications, go to Step 5.

If not within specifications, repair the harness wires between injector connectors B-01, B-02, B-05, B-06 and the ECM connector C-49 or PCM connector C-50 . Then go to Step 7.

STEP 5. Check harness connector C-49 at the ECM or harness connector C-50 at the PCM for damage.
If harness connector C-49 or C-50 is in good condition, go to Step 6.

If harness connector C-49 or C-50 is damaged, repair or replace it.
Refer to Harness Connector Inspection. Then go to Step 7.

3. Start the engine and run at idle.
4. Measure the waveform.
- The waveform should show a normal pattern similar to the illustration.

5. Turn the ignition switch to "LOCK" (OFF) position. If the waveform shows a normal pattern, it can be assumed that this malfunction is intermittent. Refer to How to Use Troubleshooting/Inspection Service Points - How to Cope With Intermittent Malfunction.

If the waveform does not show a normal pattern, replace the ECM or PCM. Then go to Step 7.

STEP 7. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Procedure 6 - Other Monitor.
2. Read the diagnostic trouble code, and confirm that diagnostic trouble codes P0201, P0202, P0203, P0204 do not reset.