Scan Tool Testing and Procedures

When troubleshooting a malfunction, the PCM/ECM and BCM data display can be used to compare the vehicle with problems to a vehicle which is functioning property.

A brief summary of each parameter is provided below:

EDO1 The Throttle Position Sensor (TPS) is displayed in degrees from -9° to 90°.

ED02 The Manifold Air Pressure Sensor (MAP) is displayed in kilopascals (kPa) from 14 to 108.

ED03 The Computed Barometric pressure (BARO) is displayed in kilopascals (kPa) from 60 to 102. The BARO reading is taken at key ON and is corrected at WOT.

ED04 The coolant temperature is displayed in degrees Celsius (°C) from -40° to 151°.

ED05 The Manifold Air Temperature Sensor (MAT) also called Air Temperature Sensor is displayed in degrees Celsius (°C) from -40° to 151°.

ED08 The spark advance display shows timing advance in degrees Before Top Dead Center (BTDC) as generated by the EST signal from the PCM/ECM from 0 to 90 degrees. If base timing is properly adjusted (10 degrees BTDC) the readings from a timing meter or timing light should agree.

ED1O The battery voltage is read in volts, from 0 to 25.6. This is the voltage measured at the fuel pump feed back at terminal F1.

ED11 The engine speed is displayed in RPM from 0 to 6370.

ED12 The vehicle speed is displayed in Miles Per Hour (MPH) from 0 to 255.

ED19 The power steering pressure sensor shows pressure in kPa from 0 to 9961.

ED30 The left injector pulse width display shows pulse width in milliseconds (ms) form 0 to 99.6.

ED31 The right injector pulse width display shows pulse width in ms from 0 to 99.6.

ED32 The left oxygen sensor voltage is displayed in volts from 0 to .99.

ED33 The right oxygen sensor voltage is displayed in volts from 0 to .99.

ED34 The left oxygen sensor cross counts displays counts from 0 to 255. The cross count is the number of times the voltage crosses the reference voltage of .45 volts in one second.

ED35 The right oxygen sensor cross counts displays counts from 0 to 255. The cross count is the number of times the voltage crosses the reference voltage of .45 volts in one second.

ED36 The left fuel integrator displays counts from 0 to 255. The normal count position for the integrator is 128, and indicates that the engine is operating normally. A count greater than 128 indicates that time is being added to the injector pulse width, which adds more 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.

ED37 The right fuel integrator displays counts from 0 to 255. The normal count position for the integrator is 128, and indicates that the engine is operating normally. A count greater than 128 indicates that time is being added to the injector pulse width, which adds more 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.

ED38 The left Block/Learn (B/L) displays counts from 0 to 255. The normal count position for the B/L is 128 and indicates that the engine is operating normally. The B/L value is based on integrator 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, which adds more 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.

ED39 The right Block/Learn (B/L) displays counts from 0 to 255. The normal count position for the B/L is 128 and indicates that the engine is operating normally. The B/L value is based on integrator 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, which adds more 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.

ED70 The 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).

ED71 This display showing 00 indicates that the 2nd gear pressure switch is closed. Display showing 01 indicates that the 2nd gear pressure switch is open.

ED72 This display showing 00 indicates that the P/N switch is closed. Display showing 01 indicates that the P/N switch is open.

ED98 The ignition cycle counter value is the number of times the ignition has been cycled to "OFF" since an PCM/ECM trouble code was last detected. After 50 ignition cycles without any malfunction being detected, all stored PCM/ECM codes are cleared.

ED99 The PCM/ECM PROM I.D. is displayed as a number up to three digits long which can be used to verify that the proper PROM is installed in the PCM/ECM.