P0202
DTC P0201: Injector Circuit - Cylinder 1, DTC P0202: Injector Circuit - Cylinder 2, DTC P0203: Injector Circuit - Cylinder 3, DTC P0204: Injector Circuit - Cylinder 4Injector Circuit Part 1:
Injector Circuit Part 2:
CIRCUIT OPERATION
- The power for the injector is supplied by the No.4 terminal of the MFI relay via an injector resistor.
- The ECM controls the injector by turning the power transistor in the ECM "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 ECM.
- A surge voltage is generated when the injectors are driven and the current flowing to the injector coil is shut off.
- The ECM checks this surge voltage.
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
DTC SET CONDITIONS
Logic Flow Chart:
Logic Flow Chart
Check Condition
- Engine is running.
Judgment Criterion
- Injector coil surge voltage (battery positive voltage +2 volts) has not been detected for 2 seconds.
OBD-II DRIVE CYCLE PATTERN
Refer to Diagnostic Function - OBD-II Drive Cycle - Pattern 23. OBD-II Drive Cycle Pattern Lists
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Injector failed.
- Injector resistor failed.
- Open or shorted injector circuit, harness damage, or connector damage.
- ECM failed.
DIAGNOSIS
Required Special Tools:
- MB991958: Scan Tool (M.U.T.-III Sub Assembly)
- MB991824: V.C.I.
- MB991827: USB Cable
- MB991911: Main Harness B
- MB991348: Test Harness Set
STEP 1. Using scan tool MB991958, check actuator test item 01, 02, 03, 04: Injectors.
CAUTION: To prevent damage to scan tool MB991958, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991958.
1. Connect scan tool MB991958 to the data link connector.
2. Start the engine and run at idle.
3. Set scan tool MB991958 to the actuator testing mode for item 01, 02, 03, 04 Injectors.
4. Warm up the engine to normal operating temperature: 80 degrees C to 95 degrees C (176 degrees F to 203 degrees F).
- The idle should become slightly rougher.
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.
NO: Go to Step 2.
STEP 2. Check the harness connector at injector for damage.
a. Check connector B-22 at No.1 cylinder.
b. Check connector B-20 at No.2 cylinder.
c. Check connector B-18 at No.3 cylinder.
d. Check connector B-17 at No.4 cylinder.
Q: Is the harness connector in good condition?
YES: Go to Step 3.
NO: Repair or replace it. Then go to Step 14.
STEP 3. Check harness connector B-119 at injector resistor for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 4.
NO: Repair or Replace it. Then go to Step 14.
STEP 4. Check the injector.
1. Disconnect the injector connector B-22
2. Measure the resistance between injector side connector terminal No.1 and No.2.
Standard value: 2 - 3 Ohms [at 20 degrees C (68 degrees F)]
Q: Is the measured resistance between 2 and 3 Ohms [at 20 degrees C (68 degrees F)]?
YES: Go to Step 5.
NO: Replace the injector. Then go to Step 14.
STEP 5. Check the injector resistor.
1. Disconnect the injector resistor connector B-119.
2. Measure the resistance between the terminals in the connector of the injector resistor.
Q: Is the measured resistance between 5.8 and 6.2 Ohms [at 20 degrees C (68 degrees F)]?
YES: Go to Step 6.
NO: Replace the injector resistor. Then go to Step 14.
STEP 6. Measure the power supply voltage at injector resistor.
1. Disconnect the connector B-119 and measure the harness side.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal No.3 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 harness connector B-12X at MFI relay for damage.
Q: Is the harness connector in good condition?
YES: Check harness connector C-105 at intermediate connector for damage, and repair or replace as required. If the intermediate connector is in good condition, repair the harness wire between MFI relay connector B-12X (terminal No.4) and injector resistor connector B-119 (terminal No.3) because of open circuit or short circuit to ground. Then go to Step 14.
NO: Repair or replace it. Then go to Step 14.
STEP 8. Measure 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 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 9.
NO: Repair harness wire between injector resistor connector and injector connector because of open circuit or short circuit to ground.
a. Repair harness wire between injector resistor connector B-119 (terminal No.1) and injector connector B-22 (terminal No.1) when checking No.1 cylinder.
b. Repair harness wire between injector resistor connector B-119 (terminal No.4) and injector connector B-20 (terminal No.1) when checking No.2 cylinder.
c. Repair harness wire between injector resistor connector B-119 (terminal No.5) and injector connector B-18 (terminal No.1) when checking No.3 cylinder.
d. Repair harness wire between injector resistor connector B-119 (terminal No.6) and injector connector B-17 (terminal No.1) when checking No.4 cylinder.
Then go to Step 14.
STEP 9. Check for harness damage between injector resistor connector and injector connector.
a. Check the harness wire between injector resistor connector B-119 (terminal No.1) and injector connector B-22 (terminal No.1) at No.1 cylinder.
b. Check the harness wire between injector resistor connector B-119 (terminal No.4) and injector connector B-20 (terminal No.1) at No.2 cylinder.
c. Check the harness wire between injector resistor connector B-119 (terminal No.5) and injector connector B-18 (terminal No.1) at No.3 cylinder.
d. Check the harness wire between injector resistor connector B-119 (terminal No.6) and injector connector B-17 (terminal No.1) at No.4 cylinder.
Q: Is the harness wire in good condition?
YES: Go to Step 10.
NO: Repair it. Then go to Step 14.
STEP 10. Check for harness damage between MFI relay connector B-12X (terminal No.4) and injector resistor connector B-119 (terminal No.3).
NOTE: Check harness after checking intermediate connector C-105. If the intermediate connector is damaged, repair or replace it. Then go to Step 14.
Q: Is the harness wire in good condition?
YES: Go to Step 11.
NO: Repair it. Then go to Step 14.
STEP 11. Check harness connector C-121 at ECM for damage.
Q: Is the harness connector in good condition?
YES: Go to Step 12.
NO: Repair or replace it. Then go to Step 14.
STEP 12. Check for open circuit and short circuit to ground and harness damage between injector connector and ECM connector.
a. Check the harness wire between injector connector B-22 (terminal No.2) and ECM connector C-121 (terminal No.1) at No.1 cylinder.
b. Check the harness wire between injector connector B-20 (terminal No.2) and ECM connector C-121 (terminal No.9) at No.2 cylinder.
c. Check the harness wire between injector connector B-18 (terminal No.2) and ECM connector C-121 (terminal No.24) at No.3 cylinder.
d. Check the harness wire between injector connector B-17 (terminal No.2) and ECM connector C-121 (terminal No.2) at No.4 cylinder.
Q: Is the harness wire in good condition?
YES: Go to Step 13.
NO: Repair it. Then go to Step 14.
STEP 13. Using the oscilloscope, check the injector.
1. Disconnect the injector connector B-22
2. Connect the oscilloscope probe to the injector side connector terminal No.2.
NOTE:
When measuring with the ECM side connector, connect an oscilloscope probe to the each of the following terminals.
- ECM terminal No.1 when checking No.1 cylinder.
- ECM terminal No.9 when checking No.2 cylinder.
- ECM terminal No.24 when checking No.3 cylinder.
- ECM terminal No.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.
NO: Replace the ECM. Then go to Step 14.
STEP 14. 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 - Pattern 23. OBD-II Drive Cycle Pattern Lists
2. Check the diagnostic trouble code (DTC).
Q: Are DTC P0201, P0202, P0203 and P0204 sets?
YES: Retry the troubleshooting.
NO: The inspection is complete.