ECM Data Display
When troubleshooting a malfunction, the ECM and BCM data display can be used to compare the vehicle with problems to a vehicle which is functioning properly. A brief summary of each parameter is provided below:
ECM:
ED01 The THROTTLE POSITION (TPS) is displayed in millivolts (mv) from 0 to 5100.
ED04 The COOLANT TEMPERATURE is displayed in degrees Celsius (~C) from -40 to 151,
ED05 The MANIFOLD AIR TEMPERATURE (MAT) also called Air Temperature Sensor is displayed in degrees Celsius (~C) from - 40 to 151.
ED06 The INJECTOR PULSE WIDTH is displayed in Milliseconds (MS), from 0 to 1002.
ED07 The OXYGEN SENSOR VOLTAGE is displayed in Millivolts (mv) from 0 to 1128 mv.
ED08 The SPARK ADVANCE value is displayed in degrees, from 0 to 70.
ED09 The TORQUE CONVERTER CLUTCH (TCC) is displayed as a 1 if the ECM is commanding the TCC to engage or a 0 if the ECM is commanding the TCC off. Actual operation depends on the integrity of the TCC system.
ED10 The BATTERY VOLTAGE is read in volts, between 0 and 25.5.
ED11 The ENGINE SPEED is displayed in RPM from 0 to 6375.
ED12 The VEHICLE SPEED is displayed in Miles Per Hour (MPH) from 0 to 159.
ED15 The OPERATING MODE is displayed as a 1 if the ECM is operating in closed loop (CL) or a 0 if the ECM is operating in open loop (OL).
ED16 The Knock Retard (ESC) is displayed in degrees of timing pulled out, from 0 to 45.
ED17 The KNOCK SENSOR ACTIVITY OLD) PA3) is displayed as counts. This counter changes whenever the ESC line is LO, which indicates sensor activity (detonation).
ED18 The OXYGEN SENSOR CROSS COUNTS is displayed as the number of times the O2 sensor crossed the reference line each second.
ED19 The FUEL INTEGRATOR is displayed in counts, from 0 to 255.
ED20 The BLOCK LEARN MULTIPLIER (BLM) is displayed in counts, from 0 to 255.
ED21 The MASS AIR FLOW (MAF) is displayed in grams per second of air flow from 0 to 255.
ED22 The IDLE AIR CONTROL (IAC) is displayed in steps of travel from 0 to 255.
ED23 The ENGINE LOAD (LV8) is displayed in counts from 0 to 255.
ED98 The IGNITION CYCLE COUNTER value is the number of times the ignition has been cycled to "OFF" since an ECM Trouble Code was last detected. After 50 ignition cycles without any malfunction being detected, all stored ECM codes are cleared.
ED99 The 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 ECM.
Input Displays
When troubleshooting a malfunction, the ECM, BCM, or IPC input display can be used to determine if the switched inputs can be properly interpreted. When one of the various input tests is selected, the state of that device is displayed as HI or LO. In general, the HI and LO refer to the input terminal voltage for that circuit. The display also indicates if the input changed state so that the technician could activate or deactivate any listed device and return to the display to see if it changed state. If a change of state occurred, an "X" will appear next to the HI/LO indicator, otherwise a "O" will remain displayed. The "X" will only appear once per selected input, although the HI/LO indication will continue to change as the input changes. Some tests are momentary and the "X" can be used as an indication of a change. The following is a list of ECM, BCM and IPC inputs:
ECM:
EI60 The EVRV display is "LO" when the EGR is On.
EI74 The PARK-NEUTRAL (P/N) displays "LO" when the vehicle is in Park or Neutral.
EI78 The POWER STEERING PRESSURE SWITCH display is "LO" when power steering pressure (effort) is high, wheel in cramp position.
EI82 The FOURTH GEAR SWITCH is "HI" when the vehicle is in fourth gear.
Output Displays
When troubleshooting a malfunction, the ECM and BCM output cycling can be used to determine if the output tests can be actuated regardless of the inputs and normal program instructions. Once a test in outputs has been selected, except for ECM IAC, the test will display HI and LO for three seconds in each state to indicate the command and output terminal voltage. A brief summary of each output is provided below:
ECM:
EO00 The NO OUTPUT'S display will not display "HI" nor "LO" as this is a resting spot where no outputs will be cycled.
EO01 The CANISTER PURGE SOLENOID display will be "LO" when the solenoid is on (energized).
EO02 The TORQUE CONVERTER CLUTCH (TCC) display will be "LO" when the TCC is on (energized).
EO04 The EGR SOLENOID display will be "LO" when the EGR Solenoid is "ON (energized).
EO07 The IAC MOTOR does not cycle "HI" or "LO" but instead extends the pintel all the way out and holds it there so minimum air adjustment can be made.
EO08 The A/C CLUTCH display will be "HI" when the clutch is on (energized).
EO09 The COOLANT FAN RELAY display is "LO" when the coolant fan is "ON (energized).