ECM Location:

The Electronic Control Module (ECM), located above the passenger kick pad, is the control center of the feedback M/C carburetor system. It constantly looks at the information from various sensors, and controls the systems that affect vehicle performance. The ECM performs the diagnostic function of the system. It can recognize operational problems, alert the driver through the "CHECK ENGINE" light, and store a code or codes which identify the problem areas to aid the technician in making repairs.

PROM (Programmable Read Only Memory):

To allow one model of ECM to be used for many different cars, a device called a PROM is used. The PROM is located inside the ECM, and contains program information tailored to the vehicle's weight, engine, transmission, axle ratio, and several other factors. While one ECM part number can be used by many car lines, a PROM is very specific and must be used for the right car. For this reason, it is very important to check the latest parts book and Service Bulletin information for the correct part number when replacing a PROM.

When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

• You smell fuel, burning insulation, or see smoke.

• Brakes feel soft, pull hard to one side, or make grinding noises.

• The engine overheats, stalls repeatedly, or misfires under load.

• You are missing required tools, torque specs, or safe lifting equipment.

• You are not confident in the next step or safety outcome.

Safety Warning

Engine Control Module: Description and Operation

ECM Location:

PROM (Programmable Read Only Memory):

Use the Manual With the Right Hardware

When to See a Mechanic