Grand AM L4-138 2.3L VIN A MFI (1992)
Step 1: Check the problem
Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have
narrowed down the possible causes.
Step 2: Read the electrical schematic
Study the schematic. Read the Circuit Description text if you do not understand how the circuit should work. Check circuits that share wiring with
the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details pages.)
Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the
problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty.
Step 3: Find the fault and repair
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Narrow down the possible causes.
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Use the Troubleshooting Hints.
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Make the necessary measurements or checks as given in the System Diagnosis.
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Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are
OK, the most probable cause is component failure.
Step 4: Test the repair
Repeat the System Check to verify the fault has been corrected and that no other faults were induced during the repair.
EXAMPLE:
A customer brings in a vehicle and says that the HI beams do not work.
Step 1: Perform a system check on the headlight circuit. You may discover that both LO beams operate. In "HI," you may notice that the HI Beam
Indicator comes on, but neither HI beam operates.
Fig. 1 Typical Headlights Schematic
Step 2: Read the headlights electrical schematic, see Fig.5 This is the step that will save time and labor. Remember, it is essential to understand
how a circuit should work, before trying to figure out why it doesn't.
After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the
