Circuit Description
The PCM will enable an injector on the intake stroke of each cylinder. Individual cylinder fuel control is referred to as Sequential Multiport Fuel Injection (SFI).
Ignition voltage is supplied directly to the fuel injectors. The PCM controls each injector by grounding the control circuit via an internal switch called a driver. The primary function of the driver is to supply the ground for the component being controlled.
Diagnostic Aids
| • | If an injector is disconnected while the engine is operating the injector driver will be disabled for the entire ignition cycle. |
| • | When the injector driver is disabled, an engine misfire will be apparent and a misfire DTC will set. |
For intermittents, refer to Symptoms .
Test Description
The numbers below refer to step numbers on the diagnostic table.
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Determines if a malfunction is present. For any test that requires probing the PCM or a component harness connector, must use the Connector Test Adapter Kit J 35616-A. Using this kit will prevent damage to the harness connector terminals.
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There are two ways to isolate a malfunctioning injector circuit:
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Check injector connections before replacing the injector. A faulty connection will cause an inoperative injector.
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Checks for an ignition feed circuit that is shorted to ground.
| • | DTC P0300 indicates a misfire is present. So use misfire current counters to locate the cylinder that is misfiring. |
| • | If no misfire DTC is present, Start and idle the engine while monitoring misfire current counters. If a misfire is present, the misfire current counters will increase for a cylinder that has a misfire. |
Disconnecting the PCM will allow using the DMM (J 39200) to check continuity of the circuits. This will aid in locating an open or shorted circuit.
Step | Action | Value(s) | Yes | No | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | Go to A Powertrain On Board Diagnostic (OBD) System Check | |||||||
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Important: This table assumes that there are no Ignition Coil/Module circuit malfunctions or mechanical malfunctions. If you were not sent here from DTC P0300, refer to DTC P0300 before proceeding with this table.
Are any of the Misfire Cur. Counters incrementing? | -- | |||||||||
Using a scan tool, monitor the Misfire Hist. Counters on the Misfire Data List (There are a total of 8 counters. One counter per cylinder.) Do any of the Misfire Hist. Counters indicate a number other than 0.0 counts? | -- | Refer to Diagnostic Aids | ||||||||
4 | Are the injector fuses OK? | -- | ||||||||
5 |
Does the test lamp illuminate? | -- | ||||||||
Does the test lamp blink? | -- | |||||||||
7 |
Did the terminal need replacing? | -- | System OK | |||||||
8 |
Does the test lamp illuminate? | -- | ||||||||
Using a DMM (J 39200), measure resistance of each injector that is powered by the fuse that was open. Does any injector measure less than the specified value? | 11.4ohms | |||||||||
10 | Repair the injector ignition feed circuit to isolated injector. Refer to Body and Accessories/Wiring Systems . Is the action complete? | -- | System OK | -- | ||||||
11 |
Is the injector driver circuit open or shorted to ground? | -- | ||||||||
12 | Repair injector driver circuit for an open or short to ground. Refer to Body and Accessories/Wiring Systems . Is the action complete? | -- | System OK | -- | ||||||
13 | Repair the grounded ignition feed circuit to the injectors. Refer to Body and Accessories/Wiring Systems . Is the action complete? | -- | System OK | -- | ||||||
14 | Repair intermittent short to ground in the injector ignition feed circuit. Refer to Body and Accessories/Wiring Systems . Is the action complete? | -- | System OK | -- | ||||||
15 | Replace the faulty injector(s) that was isolated. Refer to Fuel Injector Replacement . Is the action complete? | -- | System OK | -- | ||||||
16 |
Important:: Program the replacement PCM. Refer to PCM/TAC Module Replacement . Replace the PCM. Is the action complete? | -- | System OK | -- | ||||||
17 |
Did you find and correct the condition? | -- | System OK | Intermittent condition. Go to Symptoms |
