Inspection Procedure 5

Ignition Circuit:

Cranks, Won't Start Circuit

CIRCUIT OPERATION
- The battery positive voltage is applied on the ignition coil by the ignition switch-IG.
- When the PCM turns the power transistor in the PCM "OFF", battery positive voltage is applied on the ignition power transistor (terminals 1, 2 and 3), and the ignition power transistor turns "ON".
- When the ignition power transistor turns ON, the ignition coil's primary circuit is grounded by the ignition power transistor terminal 2. Then the primary current flows to the ignition coil.

COMMENT
- In cases such as the above, the cause is probably no spark, fuel delivery, or fuel quality problems.

In addition, foreign materials (water, kerosene, etc.) may be mixed with the fuel.

TROUBLESHOOTING HINTS
The most likely causes for this case:
- Malfunction of the ignition system.
- Malfunction of the fuel pump system.
- Malfunction of the injector system.
- Malfunction of the immobilizer system.
- Malfunction of the PCM.
- Foreign materials in fuel.

DIAGNOSIS
Required Special Tools:
MB991502: Scan Tool (MUT-II)
MB991348: Test Harness

STEP 1. Check the battery voltage.
1. Measure the battery voltage during cranking.

- The voltage should be 8 volts or more.

If the voltage is 8 volts or more, go to Step 2.

If the voltage is less than 8 volts, check the battery. Refer to Battery. Then confirm that the malfunction symptom is eliminated.

CAUTION: To prevent damage to the scan tool, turn the ignition switch "OFF" before connecting or disconnecting the scan tool.




STEP 2. Using scan tool MB991502, read the immobilizer system diagnostic trouble code (DTC).
If the immobilizer system DTC is output, refer to Ignition Switch and Immobilizer system.

If the immobilizer system DTC is not output, go to Step 3.

STEP 3. Check the timing belt for breaks.
If the timing belt is not broken, go to Step 4.

If the timing belt is broken, replace the timing belt. Then confirm that the malfunction symptom is eliminated.

CAUTION: To prevent damage to the scan tool, turn the ignition switch "OFF" before connecting or disconnecting the scan tool.




STEP 4. Using scan tool MB991502, check data list and actuator test.
1. Check the following items in the data list.
Refer to Data List Reference Table.

a. Item 16: Power Supply Voltage.
b. Item 22: Crankshaft Position Sensor.
c. Item 21: Engine Coolant Temperature Sensor.

2. Check the following items in the actuator test.
Refer to Actuator Test Reference Table.

a. Item 07: Fuel Pump.

If the checks above meet the specifications, go to Step 5.

If the checks above do not meet the specifications, repair or replace. Then confirm that the malfunction symptom is eliminated.




STEP 5. Check the circuit at the ignition power transistor connector A-06.
1. Disconnect connector A-06, and connect the test harness special tool (MB991348) in between.
(All terminals should be connected.)
2. Connect the tachometer to terminals 11, 12 and 13 in that order.
3. Crank the engine.
- The tachometer should indicate a speed that is 1/3 of the cranking speed.

If the cranking speed is normal, go to Step 6.

If the cranking speed is not normal, refer to INSPECTION PROCEDURE 31 - Ignition Circuit System.

STEP 6. Check the ignition timing.
1. Check the ignition timing at cranking.

Standard value: 50 BTDC 30 If within specifications, go to Step 7.

If not within specifications, check that the crankshaft position sensor and timing belt cover are in the correct position. Then confirm that the malfunction symptom is eliminated.

STEP 7. Check the injector operation sound.
1. Using a stethoscope or long flat-tipped screwdriver, check the operation sound ("tick-tick-tick") of injectors during cranking.

- Can the operating sound be heard? If no, go to Step 8.

If yes, go to Step 11.




STEP 8. Check the power supply line at injector connectors A-70, A-71, A-72, A-73, A-74, A-75.
1. Disconnect connectors A-70, A-71, A-72, A-73, A-74,A-75 and measure at the harness side.

2. Turn the ignition switch "ON".
3. Measure current while connecting terminal 1 to ground via a 20-ohms resistor.

- Current should be 0.5 ampere or more.

4. Turn the ignition switch "OFF".
If 0.5 ampere or more, go to Step 9.

If less than 0.5 ampere, check intermediate connector A-04, and repair or replace if necessary. Refer to vehicle level Testing and Inspection. If connector A-04 is in good condition, repair the harness wire between MFI relay connector C-59 and injector connectors A-70, A-71, A-72, A-73, A-74, A-75. Then check that the malfunction is eliminated.




STEP 9. Check the circuits at PCM connector C-89.
1. Disconnect connector C-89 and measure at the harness side.
2. Disconnect PCM connector C-90. Using a jumper wire, connect terminal 49 to ground. Then operate the MFI relay.
3. Turn the ignition switch "ON".
4. Connect terminals 1, 2, 9, 10, 24, 25 to ground via a 20-ohms resistor to measure the current at each injector as follows:

Terminal 1 for the number 1 cylinder injector
Terminal 9 for the number 2 cylinder injector
Terminal 24 for the number 3 cylinder injector
Terminal 2 for the number 4 cylinder injector
Terminal 10 for the number 5 cylinder injector
Terminal 25 for the number 6 cylinder injector

- Current should be 0.3 ampere or more.







5. Turn the ignition switch "OFF".
If 0.3 ampere or more, go to Step 10.

If less than 0.3 ampere, check intermediate connector A-04. Repair or replace if necessary. Refer to vehicle level Testing and Inspection. If intermediate connector A-04 is in good condition, repair the harness wire between injector connectors A-70, A-71, A-72, A-73, A-74, A-75 and PCM connector C-89. Then check that the malfunction is eliminated.




STEP 10. Check harness connector C-89 at the PCM for damage.
If harness connector C-89 is in good condition, replace the injector.

If harness connector C-89 is damaged, repair or replace it. Refer to vehicle level Testing and Inspection.

Then check that the malfunction is eliminated.

STEP 11. Check the following items.
1. Check the following items, and repair or replace the defective items.

a. Check the ignition coil, spark plugs, spark plug cables.
b. Check if the injectors are clogged.
c. Check if the foreign materials (water, kerosene, etc.) got into fuel.
d. Check compression.

Then confirm that the malfunction symptom is eliminated.