P0203
Injector Circuit - Cylinder 3:
Connectors:
DTC P0203: Injector Circuit Malfunction - Cylinder 3
CIRCUIT OPERATION
- The injector power is supplied from the MFI relay (terminal No. 4).
- The ECM
TECHNICAL DESCRIPTION
- The amount of fuel injected by the injector is controlled by the amount of continuity time the coil is grounded by the ECM
- A surge voltage is generated when the injectors are driven and the current flowing to the injector coil is shut off.
- The ECM
DESCRIPTIONS OF MONITOR METHODS
Off-surge does not occur after injector is operated.
MONITOR EXECUTION
Continuous
MONITOR EXECUTION CONDITIONS (OTHER MONITOR AND SENSOR)
Other Monitor (There is no temporary DTC stored in memory for the item monitored below)
- Not applicable
Sensor (The sensor below is determined to be normal)
- Not applicable
Logic Flow Chart:
DTC SET CONDITIONS
Check Conditions
- Engine is running.
Judgment Criteria
- Injector coil surge voltage (battery positive voltage + 2 volts) has not been detected for 2 seconds.
OBD-LL DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Procedure 6 - Other Monitor.
TROUBLESHOOTING HINTS (the most likely causes for this code to be set are: )
- No.3 cylinder injector failed.
- Open or shorted injector circuit, or harness damage, or connector damage.
- ECM failed.
- PCM failed.
DIAGNOSIS
Required Special Tools:
- MB991502: Scan Tool (MUT-II)
- MD998464: Test Harness
STEP 1. Using scan tool MB991502, check actuator test item 03: No. 3 injector.
CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.
1. Connect scan tool MB991502 to the data link connector.
2. Start the engine and run at idle.
3. Set scan tool MB991502 to the actuator testing mode for item 03 No. 3 injector.
4. Warm up the engine to normal operating temperature: 80 °C to 95 °C (176 °F to 203 °F).
- Does the idle state worsen when the injector is cut off. (Does idling become unstable or does the engine stall)
5. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the actuator operating properly?
YES: It can be assumed that this malfunction is intermittent.
Refer to INTRODUCTION, How to Use Troubleshooting/Inspection Service Points.
NO: Go to Step 2.
STEP 2. Check connector B-118 at injector intermediate connector for damage.
Q: Is the connector in good condition?
YES: Go to Step 3.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 3. Measure the No. 3 cylinder injector resistance at injector intermediate connector B-118.
1. Disconnect the injector intermediate connector B-118.
2. Measure the resistance between terminal No. 1 and No. 3.
- Resistance should be between 13 and 16 ohms.
Q: Is the measured resistance between 13 and 16 ohms?
YES: Go to Step 6.
NO: Go to Step 4.
STEP 4. Check the connector B-05 at No. 3 cylinder injector for damage. Remove the intake manifold.
Q: Is the harness connector in good condition?
YES: Go to Step 5.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 5. Check the No. 3 cylinder injector.
1. Disconnect the No. 3 cylinder injector connector B-05.
2. Measure the resistance between injector side connector terminals No. 1 and No. 2.
Standard value: 13 - 16 ohms @ 20 °C (68 °F)
Q: Is the resistance between 13 and 16 ohms @ 20 °C (68 °F)?
YES: Repair harness wire between No. 3 cylinder injector intermediate connector B-118 (terminal No. 1) and injector connector B-05 (terminal No. 1) and harness wire between No. 3 cylinder injector connector B-05 (terminal No. 2) and injector intermediate connector B-118 (terminal No. 3) because of open circuit or short circuit to ground or harness damage. Then go to Step 12.
NO: Replace the No. 3 cylinder injector. Then go to Step 12.
STEP 6. Measure the power supply voltage at injector intermediate connector B-118.
1. Disconnect the connector B-118 and measure at the female connector side.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No. 1 and ground.
- Voltage should be battery positive voltage.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is battery positive voltage (approximately 12 volts) present?
YES: Go to Step 8.
NO: Go to Step 7.
STEP 7. Check connector A-18X at MFI relay for damage.
Q: Is the connector in good condition?
YES: Repair harness wire between MFI relay connector A-18X (terminal No. 4) and injector intermediate connector B-118 (terminal No. 1) because of open circuit or short circuit to ground. Then go to Step 12.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 8. Check for harness damage between MFI relay connector A-18X (terminal No. 4) and injector intermediate connector B-118 (terminal No. 1).
Q: Is the harness wire in good condition?
YES: Go to Step 9.
NO: Repair it. Then go to Step 12.
STEP 9. Check connector C-111 at ECM
Q: Is the connector in good condition?
YES: Go to Step 10.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 12.
STEP 10. Check for open circuit and short circuit to ground and harness damage between injector intermediate connector B-118 (terminal No. 3) and ECM connector C-111 (terminal No. 24)
Q: Is the harness wire in good condition?
YES: Go to Step 11.
NO: Repair it. Then go to Step 12.
STEP 11. Using the oscilloscope, check the No. 3 cylinder injector.
1. Disconnect the injector intermediate connector B-118 and connect the test harness special tool (MD998464) in between.
2. Connect the oscilloscope probe to injector intermediate connector terminal No. 3 (blue clip of special tool).
NOTE: Connect the oscilloscope probe to terminal No. 24 by backprobing when measuring with the ECM or PCM connector.
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 the "LOCK" (OFF) position.
Q: Is the waveform normal?
YES: It can be assumed that this malfunction is intermittent.
Refer to INTRODUCTION, How to Use Troubleshooting/Inspection Service Points.
NO: Replace the ECM or PCM. Then go to Step 12.
STEP 12. 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 - Procedure 6 - Other Monitor.
2. Check the diagnostic trouble code (DTC).
Q: Is DTC P0203 set?
YES: Retry the troubleshooting.
NO: The inspection is complete.