DESCRIPTION & OPERATION
Input signals from sensors are sent to the Powertrain Control Module (PCM). The PCM can determine when the time and conditions are right for a shift or converter clutch application. The PCM can also determine line pressure needed to optimize shift feel.
The PCM controls transmission operation through 5 electronic solenoids consisting of 4 On/Off solenoids for shifting and torque converter clutch control and one variable force solenoid for line pressure control. All components are part of the transmission solenoid body and are not serviceable individually. The PCM has built-in self-diagnostic capability, fail-safe code and warning code display for the main input sensors and solenoid valves.
Note. In addition to transmission fault codes, engine related fault codes may be output during QUICK TEST procedure. These fault codes pertain to engine performance and must be repaired first, as engine performance will greatly affect transmission operation. For information and testing procedures of engine related fault codes and components, see the appropriate TESTS W/CODES article in ENGINE PERFORMANCE.
Engine Identification (ID) Codes
Engine ID codes are issued at beginning of KOER SELF-TEST. Codes are one-digit numbers represented by number of pulses displayed. (Схема №5) Engine ID code is equal to one-half the number of engine cylinders. For example, 2 pulses would indicate that engine is a 4 cylinder. ID code is used to verify proper PCM is installed and that SELF-TEST has been entered.
DESCRIPTION
Following procedures are functional tests of EEC-IV system. The following 4 basic test steps must be carefully followed in sequence, otherwise misdiagnosis or replacement of non-faulty components may result
- VISUAL CHECK
- EQUIPMENT HOOKUP.
- KOEO (Key On Engine Off) SELF-TEST.
- KOER (Key On Engine Running) SELF-TEST.
HARDWARE LIMITED OPERATIONAL STRATEGY (HLOS)
If a number of system or sensor failures are present and PCM is not receiving enough information to operate, PCM will switch to HLOS mode. PCM will output fixed values to allow operation of vehicle. Driveability concerns will be present. PCM will not output service codes in this mode.