Engine Control Module: Service and Repair
REMOVAL/INSTALLATION- Disconnect the negative battery cable.
- Remove the rear console, front console and undercover.
- Remove in the order shown in the figure.
- Install in the reverse order of removal.
PCM Removal/Installation:
1. PCM connectors
2. Powertrain control module (PCM)
INSPECTION
CAUTION: The PCM terminal voltages vary with change in measuring conditions and vehicle conditions. Always carry out a total inspection of the input systems, output systems, and PCM to determine the cause of trouble. Otherwise, a wrong diagnosis will be made.
- Disconnect the negative battery cable.
- Remove the rear console, front console and undercover.
- Disconnect the PCM connector.
- Connect the SST (Harness adapter) to the PCM connector.
- Connect the SSTs (Engine Signal Monitor and Harness adapter, power) to the SST (Harness adapter). Use connector A of the harness adapter for PCM terminals 1A through 1V and 3A through 3R Use connector B for PCM terminals 2A through 2L and 4A through 4Z.
- Place the SST (Sheet) on the SST (Engine Signal Monitor).
- Measure the voltage at each PCM terminal by switching the selector switch and the monitor switch.
- It any incorrect voltage is detected, check related systems, wiring harnesses and connectors referring to the possible malfunction in the terminal voltage list.
CAUTION:
- Disconnecting the connectors of the PCM and the SST (Harness adapter) while the battery is connected can damage the PCM and the SST (Engine Signal Monitor). Disconnect the negative battery cable and the SST (Harness adapter, power) before disconnecting the connectors.
- Applying voltage to terminals A and B of the SST (Engine Signal Monitor) can damage the SST (Engine Signal Monitor).
NOTE:
- The indicator lights of the SST (Engine Signal Monitor), provided for confirmation of the voltmeter range, is also used for detection of the pulse such as the fuel injector control signal, which is difficult to detect by using the voltmeter.
- Terminals A and B of the SST (Engine Signal Monitor) are for connection of an external instrument. By connecting an external instrument such as a circuit tester or an oscilloscope, various inspections in addition to the measurement of the PCM terminal voltages are made possible.
USING THE SPECIAL SERVICE TOOLS (NGS)
- In the passenger compartment, connect the SSTs (NGS) to the data link connector-2 as shown in the figure.
- Referring to the NGS instruction manual, select the "PID/DATA MONITOR AND RECORD" function.
- Referring to the 1996 Service Highlights, inspect each PCM input/output signal.
NOTE:
- The "PID/DATA MONITOR AND RECORD" function is to monitor the calculation value of input/output signals in the PCM. Deviation in the value does not always indicate malfunction in the related input/output devices.
- When normal output signal cannot be detected when all input signals are normal, replace the PCM.
Terminal Voltage References Part 1 of 5:
Terminal Voltage References Part 2 of 5:
Terminal Voltage References Part 3 of 5:
Terminal Voltage References Part 4 of 5:
Terminal Voltage References Part 5 of 5:
TERMINAL VOLTAGE (REFERENCE) CHARTS