Scan Tool Testing and Procedures

The Diagnostic Parameters section is divided into three parts:

^ IPC Data Displays

^ IPC Input Displays

^ IPC Output Override Displays

The IPC Data Displays comprise those system input signals containing a Byte of information, generally, but not exclusively, expressed as a value between 0 and 255 counts. The IPC Data Displays may be called up only with the service diagnostics or scan tool.

IPC Input Displays are those inputs which can be represented with a single bit of information. These system signals are represented by a HIGH/LOW designation, HIGH begin equal to a "digital 1" and LOW being equal to a digital "0". The IPC Input displays may only be viewed using the service diagnostics.

IPC Output Override Displays contain information on default option conditions for the vehicle. These default conditions include:

- DIC message display suppression

- Optional Equipment Installations

- Export Country

- HVAC Mode Selections

IPC Data Displays:

IPD01 This displays the A/D value for the dimming potentiometer on the headlamp switch. This value can slew from 0 to 155 counts under normal operation. Significantly higher values (200 and higher) indicate problems in the circuit.

IPD02 BATTERY VOLTS is displayed in volts between 8.7 and 18.0, on Connector C1 terminals "A1" and "B1" (Controlled Power).

IPD03 The VEHICLE SPEED is shown in miles per hour between 0 and 255.

IPD04 The LOW BRAKE FLUID signal is shown in volts between 0 and 5 volts. 0 volts - low brake fluid or a short to ground in the Low Brake Fluid Switch CKT. 5v = open in Low Brake Fluid Switch CKT. Normal signal voltage is approximately 2.5 volts.

IPD05 The STEERING WHEEL CONTROLS A/D count is displayed from the four steering column lever switch resistors at input Connector C2 terminal "B11," to decode which of eight functions is being requested. There is an invalid deadband position on each side of the eight valid A/D count/resistance values. The range of data counts is 0 to 255.

IPD06 Displays the current PASS-Key(R) II pellet A/D value on input Connector C1 terminal "A10" key high input. Data count range is 0 to 255 counts.

IPD07 The TWILIGHT DELAY POTENTIOMETER displays the current A/D value on input Connector C1 terminal "C9." The count range is 0 to 255. This count value represents the 0 to 180 second twilight delay.

IPD08 Displays the current TWILIGHT PHOTOCELL A/D count from Connector C1 "C12." This count is used to determine exterior light/dark status. Dark is normally any count above 143 and Light is any value below 123 counts. Both values may be calibrated.

IPD09 to IPD13 Displays the current EEPROM data for Option A to Option E. The data reflects the decimal equivalent of an 8-bit binary code. Range is 0 to 255. No units are associated with this number. See IPC Output Overrides IPS01 through IPS05 for recognized values of these options.

IPD14 The IGNITION CYCLE COUNTER value is the number of times that the IPC has been turned "OFF" since a IPC DTC was last detected. After 100 ignition cycles without any malfunction being detected, all IPC DTCs are cleared.

IPD98 The DCP SOFTWARE VERSION is software ID for one of the IPC microprocessors.

IPD99 The PCM SOFTWARE VERSION is software ID for the second IPC microprocessor.

IPC Input Displays:

IPI01 Displays the state of the trunk release switch input to the IPC at Connector C1 "D10." Normal state is high. When switch is actuated this level goes low.

IPI02 The WASHER FLUID LEVEL SWITCH display is "LOW" when the vehicle is low on washer fluid or input is shorted to ground.

IPI03 The ALTERNATOR L-Terminal input will display "LOW" when the ALTERNATOR is not charging. This may be due to the engine not turning or an alternator problem. In addition, if ignition 1 to the IPC is not available, this input will be low.

IPI04 The CATALYTIC CONVERTER display is "HIGH" when there is an overtemperature condition.

IPI05 The KEY IN IGNITION display is "LOW" when the key is in the ignition and the switch position is ACCY, LOCK or UNLOCK. This input will always be "HIGH" in "RUN" or "CRANK." Use a scan tool to verify switch operation.

IPI06 Starter relay diagnostics are not performed, but will show up in service diagnostics. Disregard IP106.

IPI07 The HIGH BEAM/FLASH TO PASS display is "HIGH" when the switch is "ON" (switch closed).

IPI08 The WIPER "A" display will be high whenever the wiper switch is NOT in the OFF position.

IPI09 The COOLANT LEVEL SWITCH display will be low when the fluid level is acceptable. Due to a heavy filtering algorithm, this input may toggle to high without a "Check Coolant Level" message on the DIC.

IPI10 The FAST IDLE will display "LOW" when the heated windshield module is ON.

IPI12 The INTERIOR LAMPS display is "LOW" when the interior lamps switch is closed on the headlamp switch.

IPI13 The HEADLAMP LOW BEAM display is "LOW" when the headlamp switch is closed or when the low beams are "ON" due to automatic feature (e.g. Twilight sentinel, wiper activated headlamps).

IPI14 The PARKLAMPS display is "LOW" when the parklamps switch is closed.

IPI15 The FRONT FOG LAMP display is "LOW" when the front fog lamp switch is closed.

IPI16 The REAR FOG LAMP display is "LOW" when the rear fog lamp switch is closed. Note: export only.

IPI17 The TWILIGHT ENABLE display is "HIGH" when the twilight enable switch is NOT in the OFF position. It will be low in the OFF position.

IPI18 The FUEL DOOR RELEASE display is "LOW" when the fuel door switch is closed.

IPI19 The DRIVER INFO display is "LOW" when the "INFO" switch is closed. This only applies to vehicles equipped with the Analog IPC.

IPI20 The TRIP RESET display is "LOW" when the "TRIP RESET" switch is depressed closed. This only applies to vehicles equipped with the Analog IPC.

IPI21 The RESET display is low when the "INFO RESET" switch is closed. Note: Pressing this button while in on-board diagnostics, will force the vehicle to exit service diagnostics. Check this input with a scan tool. This only applies to vehicles equipped with the Analog IPC.

IPI24 LEFT TURN SWITCH will be high when the left turn switch is ON and the output from the flasher module is on. This input will toggle with the state of the lamps (Lo/Hi).

IPI25 RIGHT TURN SWITCH will be high when the right turn switch is ON and the output from the flasher module is on. This input will toggle with the state of the lamps (Lo/Hi).

IPC Override Displays:

A set bit ("1") in an Option Byte will establish a default code for that item.

IPS00 This test will display "none" as no overrides are active at this point

IPS01 Option A
Universal Theft Deterrent Enable 8
Interior Air Purge 1

IPS02 Option B (Export Country)
European Economic Community (EEC) 16
Japan 8
Saudi Arabia 4
Canada 2
Norway/Sweden 1

These are the only values, along with these values added to sixty four (64) e.g. Norway/Sweden = 65=1, recognized by the IPC as a valid country.

IPS03 Option C
Premium Unleaded Fuel Only graphic suppression on digital IPC 64
Daytime Running Lamps 32
Cellular Telephone installed 16
Brake Transmission Shift Interlock (BTSI) Message Suppression 4
Options Not Set 2
"LOW FUEL LEVEL" message suppression 1

IPS04 Option D (HVAC Options)
Afterblow enable 128
Afterboil enable 64
De-Ice Installed 32
Timed Recirc enable 16
Dual Zone HVAC Installed 8

IPS05 Option E (DIC display options)
Coolant Temperature on DIC 64
Battery Volts on DIC 32
Engine RPM on DIC 16
Average Speed on DIC 8
Vehicle Speed on DIC 4
Fuel Used on DIC 2
Instantaneous Fuel Economy on DIC 1

IPS06 SET TEMPERATURE is used to allow the Set Temperature to be different from the commanded Set Temperature from -5°F to +5°F

IPS07 Incandescent Dimming (INC DIM A) can be slewed from OFF to full bright to check lighting.

IPS08 Incandescent Dimming (INC DIM B) can be slewed from OFF to full bright to check lighting.

IPS09 Allows Starter Enable output to be overridden for up to 5.0 seconds to verify operation. Vehicle will not start unless IPC PASS-Key(R) II keyword and PCM stored password match.

IP510 Alternator Disable. This Output is not available but has not been removed from the IPC. Changing the value will not affect the IPC in any way.

IP511 De-Ice Switch allows override of the IPC De-Ice switch output. This output will only pulse and will not be constant (i.e. High, Low, High).