P0201
Injector Circuit:
Connectors:
CIRCUIT OPERATION
- The injector power is supplied from the MFI relay (terminal 1).
- The PCM controls the injector by turning the power transistor in the PCM "ON" and "OFF".
TECHNICAL DESCRIPTION
- The amount of fuel injected by the injector is controlled by the amount of continuity time the coil is grounded by the PCM.
- A surge voltage is generated when the injectors are driven and the current flowing to the injector coil is shut off.
- The 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 2 seconds.
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Injector failed.
- Open or shorted injector circuit, or loose connector.
- PCM failed.
DIAGNOSIS
Required Special Tools
- MB991502: Scan Tool (MUT-II)
- MB991348: Test Harness
STEP 1. Using scan tool MB991502, check actuator test item 01, 02, 03, 04: Injectors.
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 01, 02, 03. 04 Injectors.
4. Warm up the engine to normal operating temperature: 80°C to 96°C (176°F to 205°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 How to Use Troubleshooting/Inspection Service Points.
NO: Go to Step 2.
STEP 2. Check the connector at injector for damage.
a. Check the connector B-22 when checking No. 1 cylinder.
b. Check the connector B-21 when checking No. 2 cylinder.
c. Check the connector B-19 when checking No. 3 cylinder.
d. Check the connector B-17 when checking No. 4 cylinder.
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 10.
STEP 3. Check the injector.
1. Disconnect the injector connector B-22
2. Measure the resistance between injector side connector terminal 1 and 2.
Standard value: 13 - 16 ohm [at 20°C (68°F)]
Q: Is the resistance standard value?
YES: Go to Step 4.
NO: Replace the injector. Then go to Step 10.
STEP 4. Check the power supply voltage at injector connector.
1. Disconnect connector B-22
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 1 and ground.
- Voltage should be battery positive voltage.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the voltage normal?
YES: Go to Step 6.
NO: Go to Step 5.
STEP 5.Check connector A-18X at MFI relay for damage.
Q: Is the connector in good condition?
YES: Repair harness wire between MFI relay connector and injector connector because of open circuit or short circuit to ground.
a. Repair harness wire between MFI relay connector A-18X terminal 4 and injector connector B-22 terminal 1 when checking No. 1 cylinder.
b. Repair harness wire between MFI relay connector A-18X terminal 4 and injector connector B-21 terminal 1 when checking No. 2 cylinder.
c. Repair harness wire between MFI relay connector A-18X terminal 4 and injector connector B-19 terminal 1 when checking No. 3 cylinder.
d. Repair harness wire between MFI relay connector A-18X terminal 4 and injector connector B-17 terminal 1 when checking No. 4 cylinder.
Then go to Step 10.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 10.
STEP 6. Check for harness damage between MFI relay connector and injector connector.
a. Check the harness wire between MFI relay connector A-18X terminal 4 and injector connector B-22 terminal 1 when checking No. 1 cylinder.
b. Check the harness wire between MFI relay connector A-18X terminal 4 and injector connector B-21 terminal 1 when checking No. 2 cylinder.
c. Check the harness wire between MFI relay connector A-18X terminal 4 and injector connector B-19 terminal 1 when checking No. 3 cylinder.
d. Check the harness wire between MFI relay connector A-18X terminal 4 and injector connector B-17 terminal 1 when checking No. 4 cylinder.
Q: Is the harness wire in good condition?
YES: Go to Step 7.
NO: Repair it. Then go to Step 10.
STEP 7. Check connector C-39 at PCM for damage.
Q: Is the connector in good condition?
YES: Go to Step 8.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then go to Step 10.
STEP 8. Check for open circuit and short circuit to ground and harness damage between injector connector and PCM connector.
a. Check the harness wire between injector connector B-22 terminal 2 and PCM connector C-39 terminal 1 when checking No. 1 cylinder.
b. Check the harness wire between injector connector B-21 terminal 2 and PCM connector C-39 terminal 9 when checking No. 2 cylinder.
c. Check the harness wire between injector connector B-19 terminal 2 and PCM connector C-39 terminal 24 when checking No. 3 cylinder.
d. Check the harness wire between injector connector B-17 terminal 2 and PCM connector C-39 terminal 2 when checking No. 4 cylinder.
Q: Is the harness wire in good condition?
YES: Go to Step 9.
NO: Repair it. Then go to Step 10.
STEP 9. Using the oscilloscope, check the injector.
1. Disconnect the injector connector B-22
2. Connect the oscilloscope probe to the injector side connector terminal 2.
NOTE: When measuring with the PCM side connector, connect an oscilloscope probe to the each of the following terminals.
- PCM terminal 1 when checking No. 1 cylinder.
- PCM terminal 9 when checking No. 2 cylinder.
- PCM terminal 24 when checking No. 3 cylinder.
- PCM terminal 2 when checking No. 4 cylinder.
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 How to Use Troubleshooting/Inspection Service Points.
NO: Replace the PCM. Then go to Step 10.
STEP 10. Test the OBD-II drive cycle.
1. Carry out a test drive with the drive cycle pattern. Refer to Procedure 6 - Other Monitor.
2. Check the diagnostic trouble code (DTC).
Q: Is the DTC P0201, P0202, P0203, P0204 is output?
YES: Retry the troubleshooting.
NO: The inspection is complete.