Fuel Injectors, Checking
Observe all safety precautions: SAFETY PRECAUTIONS
View clean working conditions: CLEAN WORKING CONDITIONS
Use only gold-plated terminals when servicing any component with gold-plated electrical harness connector terminals.
For wiring diagrams, component locations, and connector views, Refer to the applicable SYSTEM WIRING diagram.
Special Tools And Workshop Equipment Required
- Multimeter
- Diode test lamp (12V)
- Wiring diagram
Test Requirements
- The Engine Speed (RPM) Sensor -G28- OK.
- Battery voltage at least 12.5 volts.
- All electrical consumers such as, lights and rear window defroster, switched off.
- Vehicles with automatic transmission, shift selector lever into position "P" or "N".
- A/C switched off.
- Ground (GND) connections between engine/transmission/chassis OK.
- Ignition switched off.
-- Observe safety precautions.
-- Observe rules for cleanliness.
Test Procedure
-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK
Start Diagnosis
-- Remove the engine cover and air intake duct. Refer to appropriate service information.
-- Disconnect the 8 pin connector from the fuel injector assembly harness (located just below and to the right of the electronic throttle motor assembly).
-- Using a multimeter connected to ground, check terminals 2, 4, 6, 8 for the correct voltage.
Specified Value: 22 - 25 V.
If voltage is below specification:
If the manufacturers test box is being used, perform the following step.
-- Install the test box.
If the manufacturers test box is not being used, perform the following step.
-- Remove the Motronic Engine Control Module (ECM) -J623-. Refer to appropriate service information.
-- Using a multimeter, check the Fuel Injector -- electrical harness connector terminals to the Motronic Engine Control Module (ECM) -J623- electrical harness connector T60 terminals for an open or short to ground circuit.
| Component | Fuel Injector -- Electrical Harness Connector Terminals | Motronic Engine Control Module (Ecm) -J623- Electrical Connector T60 Terminals Or Test Box Sockets |
|---|---|---|
| Cylinder 1 Fuel Injector -N30- | 2 | 33 |
| Cylinder 2 Fuel Injector -N31- | 4 | 49 |
| Cylinder 3 Fuel Injector -N32- | 6 | 34 |
| Cylinder 4 Fuel Injector -N33- | 8 | 48 |
Specified Values: 1.5 Ω max . for wire continuity, and for circuit to ground check; Infinity or "OL" is displayed
If the specification is not obtained:
-- Check the wiring for an open, high resistance or short to ground.
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the faulty wiring connection.
If voltage is within specification:
Checking internal resistance
-- Using a multimeter, check the Fuel Injector -- electrical terminals (1 to 2 for N30, 3-4 for N31, 5-6 for N32 or 7 to 8 for N33) for resistance.
Specified Value: 1.4 - 2.6 Ω (at approx. 20° C)
If the specified value was not obtained:
-- Replace the malfunctioning Fuel injector(s). Refer to appropriate service information.
If the specified value was obtained:
Checking activation and wiring
-- Connect a diode test lamp (12V) from Battery + to the injector harness connector terminal (1 for N30, 3 for N31, 5 for N32 or 7 for N33) of the Fuel Injector -- to be tested.
-- Operate the starter and test the activation of the Fuel Injector --.
LED should flicker.
-- Switch the ignition off.
If LED does not flicker:
If the manufacturers test box is being used, perform the following step.
-- Install the test box.
If the manufacturers test box is not being used, perform the following step.
-- Remove the Motronic Engine Control Module (ECM) -J623-. Refer to appropriate service information.
-- Using a multimeter, check the Fuel Injector -- electrical harness connector terminals to the Motronic Engine Control Module (ECM) -J623- electrical harness connector T60 terminals for an open circuit.
| Component | Fuel Injector -- Electrical Harness Connector Terminals | Motronic Engine Control Module (ECM) -J623- Electrical Connector T60 Terminals Or Test Box Sockets |
|---|---|---|
| Cylinder 1 Fuel Injector -N30- | 1 | 31 |
| 2 | 33 | |
| Cylinder 2 Fuel Injector -N31- | 3 (1) | 47 |
| 4 (2) | 49 | |
| Cylinder 3 Fuel Injector -N32- | 5 (1) | 32 |
| 6 (2) | 34 | |
| Cylinder 4 Fuel Injector -N33- | 7 (1) | 46 |
| 8 (2) | 48 |
Specified Value: 1.5 Ω Max.
If the specification is not obtained:
-- Check the wiring for an open, high resistance or short to battery or ground.
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the faulty wiring connection.
If no malfunction is detected in the wiring:
-- Replace the Motronic Engine Control Module (ECM) -J623-. Refer to appropriate service information.
-- Install the engine cover with air filter. Refer to appropriate service information.
Final Procedures
After the repair work, the following work steps must be performed in the following sequence:
- Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
- If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
- If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .