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Home >> Oldsmobile >> 1991 >> Toronado V6-3800 3.8L >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Testing and Inspection >> Initial Inspection and Diagnostic Overview >> - Description of On-Board Diagnostics >> Diagnostic Displays >> PCM/ECM Display >> Override

Override

When troubleshooting a malfunction, the PCM override feature allows testing of certain system functions regardless of normal program instructions. Upon selecting a test, that selections current operation will be represented as a percentage of its full range, and this value will be displayed on the ECC panel. If the selected override is not allowed under the current conditions a "--" display will result.

Touching the "WARM" or "COOL" buttons on the ECC panel begins the override. The "WARM" button will increase the value while the "COOL" button will decrease it. Normal Program control can be resumed in one of three ways:

1. Selection of another override test will cancel the current override.
2. Selection of another system will cancel the current override.
3. Overriding the value beyond either extreme (0 or 99) will display "--" momentarily and then jump to the normal program control.

The override test type is unique in that any other test type within the selected system may be active at the same time. After selecting in override test, touching the "OFF" button will allow selection of another test type, however, the ECC panel will continue to display the selected override. By selecting another test type and test, and then touching the "WARM" or "COOL" buttons, it is possible to monitor the effect of the override on different vehicle parameters.

PCM OVERRIDE DISPLAYS:

ESOO The "NONE" display will not display any value on the secondary display as this is a resting spot where no overrides will be controlled. This is a handy spot to go to stop the override without having to go back to the level where the system is selected.

ES01 The canister purge solenoid "CAN PURG" will be turned "OFF" "00" by pressing the "COOL" button, or "ON" "99" (purging) by pressing the "WARM" button.

ES02 The "A/C RELAY" can be turned "OFF" "00" by pressing the "COOL" button, or "ON" "99" (engaged) by pressing the "WARM" button.

ES03 The "IAC MOTOR" display will show the position the IAC is being commanded to in a percentage of travel. In order for this override to work the vehicle must be in park or neutral. The "COOL" button will retract the motor (increasing engine rpm) and the "WARM" button will extend the motor. The MIN AIR can be checked with an override display of 99%, which represents a fully extended IAC position.

ES04 C/C SERVO - The cruise control switch must be "ON" for this test to work. The automatic calculation of cruise control position number can be bypassed by a manual override feature using this override. "99" represents the max cruise position (WOT) and 0 represents the minimum cruise position (closed throttle). This manual override of automatic cruise control position number calculation will continue until this override is stopped. This allows the technician to control the cruise control position to any number from 0 to 99 and simultaneously observe the reaction of the data value for cruise servo position (BD70). The two should agree with each other +/- 3% except when the servo is commanded beyond its mechanical limits of travel. Since this test is not allowed with engine running, remember that there is usually only enough vacuum in the storage tank to stroke the servo once.

ESO5 The cooling fan relay #1 "FAN REL 1" can be turned "OFF" "00" by pressing the "COOL" button, or "ON" "99" (engaged) by pressing the "WARM" button.

ES06 The cooling fan relay #2 "FAN REL 2" can be turned "OFF" "00" by pressing the "COOL" button, or "ON" "99" (engaged) by pressing the "WARM" button.

ES07 The "TCC SOL" display will show the commanded state of the TCC solenoid ("00" not engaged, "99" engaged). Pressing the "WARM" button will engage the TCC and pressing the "COOL" button will disengage the TCC. the vehicle must be in 3rd or 4th gear for this override to operate.

ES08 GEAR This override places the transmission in the current gear selected and remains at that gear until the warm or cool buttons are depressed to change gear selection. The transmission will be downshifted one gear each time the cool button is depressed and upshifted on the gear each time the warm button is depressed. The PCM only allows 1st gear up to 35 mph, 2nd gear up to 50 mph, and 3rd gear up to 60 mph.

ES09 The injector control override "MS INJ PW" will work only when the vehicle is in P/N. Upon entering injector override the display will show 0, all injectors working under normal program control. The "WARM" button will increment the display by 1, up to 6 and wrap around to 0. This display number indicates the injector that is being held "OFF" (i.e., 4 = injector 4 "OFF"). The corresponding injector to the number displayed will be held "OFF" for as long as the number is displayed. The "COOL" button is used to turn the injector back "ON" and then "OFF" (toggle effect); i.e., if the display shows 4, injector 4 is "OFF." Touching "COOL" will turn injector 4 "ON," and the display will show 0. Touching "COOL" again will turn injector 4 back "OFF" and the display will show a 4. The "COOL" button toggles whatever injector you last displayed from "ON" to "OFF."
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