PCM Data

DESCRIPTION AND OPERATION
The Powertrain Control Module (PCM) data selection allows viewing of inputs the PCM uses to control powertrain functions. Each data parameter is displayed on the Driver Information Center (DIC) in appropriate units. PCM data values and definitions are as follows:

PDO1 Throttle Position (TP) Sensor
Display shows degrees of throttle opening from - 10 to 90.

PDO2 Manifold Absolute Pressure (MAP) Sensor
Display shows manifold pressure in Kilo Pascals (kPa) from 14 to 109. At key "ON" (engine not running), the MAP value will reflect barometric pressure. Multiply your local barometric pressure by 3.386 to obtain a MAP value that should be within 2 kPa of the displayed value at key "ON." At key "ON," MAP will vary with altitude.

PDO3 Barometric Pressure (BARO)
Display shows the BARO in kPa from 61 to 103. The BARO reading is taken at key "ON" and is corrected at Wide Open Throttle (WOT). Multiply your local barometric pressure by 3.386 to obtain a BARO value that should be within 2 kPa of the displayed value. BARO varies with altitude (e.g. a typical value in Denver is 85 kPa while a typical value at sea level is 100 kPa).

PD04 Engine Coolant Temperature (ECT) Sensor
Display shows the temperature of engine coolant in degrees Celsius from -40 to 151.

PD05 Intake Air Temperature (IAT) Sensor
Display shows the temperature of intake manifold air in degrees Celsius from -40 to 151.

PD08 Spark Advance
Display shows timing advance in degrees Before Top Dead Center (BTDC) as generated by the ignition control signal from the PCM from 0 to 52 degrees.
If base timing is properly adjusted (10 degrees BTDC) the readings from a timing meter or timing light should agree.

PD10 Battery Voltage
Display shows battery voltage measured at the fuel pump feedback, CKT 120, from 0 to 25.5.

PD11 Engine Speed (RPM)
Display shows crankshaft rotation speed in revolutions per minute (RPM) from 0 to 6375.

PD12 Vehicle Speed
Display shows vehicle speed in miles per hour (mph) from 0 to 255.

PD19 Transaxle Oil Temperature
Display shows the transaxle oil temperature in degrees Celsius from -40 to 152.

PD30 Front Bank Injector Pulse Width
Display shows injector pulse width for cylinders 2, 4, 6, and 8 in milliseconds (ms) from 0 to 99.9.

PD31 Rear Bank Injector Pulse Width
Display shows injector pulse width for cylinders 1, 3, 5, and 7 in milliseconds (ms) from 0.0 to 99.9.

PD32 Front Oxygen (O2S) Sensor Voltage
Display shows front O2S voltage from 0.0 to 1.16.

PD33 Rear Oxygen (O2S) Sensor Voltage
Display shows rear O2S voltage from 0 to 1.16.

PD34 Front Oxygen Sensor Cross Counts
Display shows counts from 0 to 255. The cross count is the number of times the voltage crosses the reference voltage of 0.45 volt in one second.

PD35 Rear Oxygen Sensor Cross Counts
Display shows counts from 0 to 255. The cross count is the number of times the voltage crosses the reference voltage of 0.45 volt in one second.

PD36 Front Short Term Fuel Trim
Display shows counts from 0 to 255. The normal count position for the short term fuel trim is 128. A count greater than 128 indicates that time is being added to the injector pulse width, increasing the amount of fuel to the engine to compensate for a lean condition sensed by the front O2S. A count less than 128 indicates time is being subtracted from the injector pulse width reducing the amount of fuel to the engine to compensate for a rich condition sensed at the front O2S.

PD37 Rear Short Term Fuel Trim
Display shows counts from 0 to 255. The normal count position for the short term fuel trim is 128. A count greater than 128 indicates that time is being added to the injector pulse width, increasing the amount of fuel to the engine to compensate for a lean condition sensed by the rear O2S. A count less than 128 indicates time is being subtracted from the injector pulse width reducing the amount of fuel to the engine to compensate for a rich condition sensed at the rear O2S.

PD38 Front Long Term Fuel Trim
Display shows counts from 0 to 255. The normal count position for the front long term fuel trim is 128. The front long term fuel trim value is based on short term fuel trim learned values. It is stored in memory blocks of the long term memory according to MAP and RPM values. A count greater than 128 indicates that time is being added to the injector pulse width, increasing the amount of fuel to the engine. A count less than 128 indicates time is being subtracted from the injector pulse width reducing the amount of fuel to the engine.

PD39 Rear Long Term Fuel Trim
Display shows counts from 0 to 255. The normal count position for the rear long term fuel trim is 128. The rear long term fuel trim value is based on short term fuel trim learned values. It is stored in memory blocks of the long term memory according to MAP and RPM values. A count greater than 128 indicates that time is being added to the injector pulse width, increasing the amount of fuel to the engine. A count less than 128 indicates time is being subtracted from the injector pulse width reducing the amount of fuel to the engine.

PD7O Cruise Control Feedback
Display shows the percentage of servo apply as measured by the servo position sensor with 0 equaling full relaxed (no vacuum) and 99 equaling full apply (full vacuum signal).

PD71 Transaxle Range Switch 1
PRNDL Gray Code: This display shows the status of the transaxle range switch for CKTs 773 and 772, which are Inputs "C" and "B" to the PCM. 0 indicates the switch is closed and 1 indicates the switch is open.

PD72 Transaxle Range Switch 2
PRNDL Gray Code: This display shows the status of the transaxle range switch for CKTs 771 and 776, which are Inputs "A" and "P" to the PCM. 0 indicates the switch is closed and 1 indicates the switch is open.

PD98 Ignition Cycles
Display shows counts from 1 to 50. The count increases by 1 with each "ON" to "OFF" cycle. When a trouble code sets, the counter is set to 0. If the trouble code becomes history the counter will increment with each key cycle until another code is set, or until the key has been cycled 50 times at which time the code will be erased.

PD99 PROM Calibration - Engine
Display shows a four digit code that uniquely identifies the program stored in the PROM for the engine control calibration.