Hi guys,

I've got a honda civic yr 02 model ES8 (automatic gear box), tha problem is that while driving the gears do not shift! wen to a mechanic/technician who ran some tests and finally announced with a big smile taht my pcm unit is damaged, he even removed the pcm unit and showed it to me an d really it was in a bad state. could you explain what is the real function of the pcm unit and how it has been damaged? also is it a common prob with civics??

txgreasemonkey

Various inputs to the ECM are TDC/CKP/CYP Sensor, MAP Sensor, ECT Sensor, IAT Sensor, TP Sensor, HO2S, VSS, BARO Sensor, EGR Valve Lift Sensor, Starter Signal, Alternator FR Signal, Air Conditioning Signal, Automatic Transmission Shift Position Signal, Battery Voltage (Ignition 1) Brake Switch Signal, PSP Switch Signal, ELD, and VTEC Pressure Switch.

Inputs are received and processed by the ECM's Fuel Injector Timing and Duration, Electronic Idle Control, Other Control Functions, Ignition Timing Control, and ECM Back-up Functions. These are the primary functional areas within the ECM.

Outputs from the ECM control Fuel Injectors, PGM-FI Main Relay (Fuel Pump), MIL (Check Engine Light), Idle Air Control (IAC) Valve, A/C Compressor Clutch Relay, Ignition Control Module (ICM), EVAP Purge Control Solenoid Valve, HO2S Heater, EGR Control Solenoid Valve, Alternator, Lock-up Solenoid Valve A/B (A/T), VTEC Solenoid Valve, and Interlock Control Unit.

When you remove your ECM, disconnecting the negative battery terminal first, look at the likely heat discoloration on the metal covers. You will probably observe a spiral blue pattern. ECMs don’t have fan motors to cool them and, to make matters worse, are covered by carpeting. Heat, vibration, flooding, and shorts, among other things, reduce their lives.

Replacing ECMs is not uncommon on 10+ year old Hondas; however, it is for 5 year olds--baring flooding or accidental shorting.