Diagnostics

The IPC detects various malfunctions in the following components:

When the IPC (or another microprocessor-controlled module) detects a malfunction, the following actions may occur:

Some DTCs may not cause an IPC message to be displayed. Some DTCs may not activate an IPC indicator lamp.

In order to display various IPC input and output parameters, any set DTC, and change the various IPC override options, use one of the following methods:

1. Enter the Vehicle Diagnostic System. Display the information on the IPC driver message center. Refer to Vehicle Diagnostic System.
2. Connect a scan tool to the DLC.

IPC Diagnostic Parameters

The IPC Diagnostic Parameters section is divided into three parts:

The IPC data displays comprise those system input signals that contain a byte of information (usually, but not always) between 0-255 counts. The IPC Data Displays may be called up only using the service diagnostics or the scan tool .

The IPC input displays are those inputs that are represented by a HIGH/LOW designation. HIGH is equal to voltage (digital 1). LOW is equal to ground (digital 0).

The IPC output override displays contain information on the default option conditions for the vehicle. The default conditions include the following items:

IPC Data Displays

IPD01: This code displays the value (A/D count) for the dimming potentiometer on the headlamp switch. This value ranges from 0-155 under normal operation. Higher values (200 and above) may indicate a malfunction in the circuit.

IPD02: BATTERY VOLTS is displayed in volts between 8.7-18.0 on IPC connector C1 terminal A1 and terminal B1 (Controlled Power).

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

IPD04: The LOW BRAKE FLUID signal is shown in volts between 0-5 V.

IPD05: This code displays the value (A/D count) of the steering wheel control switches at IPC connector C2 terminal B11. Refer to Entertainment in order to decode which one of the 8 functions is requested. The value may range from 0-255.

IPD06: The code displays the current PASSKey® II pellet value (A/D count) being detected at IPC connector C1 terminal A10. The value may range from 0-255. A display of 0 indicates that an invalid key code is present.

IPD07: The TWILIGHT DELAY POTENTIOMETER displays the current value (A/D count) being detected at connector C1 terminal C9. The value may range from 0-255. This count value represents the 0-180 second twilight delay.

IPD08: The TWILIGHT PHOTOCELL displays the current value (A/D count) being detected at connector C1 terminal C12. This value is used in order to determine the exterior light/dark status. Dark is normally a value above 143. Light is normally a value below 123.

IPD09 to IPD13: These codes display the current EEPROM data values for options A-E. The values reflect the decimal equivalent of an 8-bit binary code. The values may range from 0-255. No units are associated with these numbers. In order to decode these values, refer to IPC Output Overrides -- overrides IPS01-IPS05.

IPD14: The IGNITION CYCLE COUNTER displays a value that is the number of times that the IPC was turned OFF since an IPC DTC was last detected. After 50 ignition cycles without any malfunctions being detected, all IPC DTCs are cleared.

IPD98: The DCP SOFTWARE VERSION is the software ID for an IPC microprocessor.

IPD99: The CPM SOFTWARE VERSION is the software ID for an IPC microprocessor.

IPC Input Displays

IPI01: This code displays the state of the rear compartment lid release switch input to the IPC at connector C1 terminal D10. When the switch is pressed, the display is low. The normal display is high.

IPI02: The WASHER FLUID LEVEL SWITCH display is low when a low washer fluid condition exists or the input is shorted to ground.

IPI03: The ALTERNATOR L-TERMINAL display is low when the alternator is not charging. This condition may be due to one of the following problems:

IPI04: Disregard the CATALYTIC CONVERTER status.

IPI05: The KEY IN IGNITION display is low when the ignition switch is in the ACCY, LOCK, or OFF position with the key inserted. This input is high when the ignition switch is in the RUN or the START position.

IPI06: Disregard. IPI06 starter relay diagnostics are not performed. The starter relay diagnostics show up in the service diagnostics.

IPI07: The HIGH BEAM/FLASH-TO-PASS display is high when the switch is in the ON position.

IPI08: The WIPER A display is low when the wiper switch is in the OFF position.

IPI09: The COOLANT LEVEL SWITCH display is low when the engine coolant fluid level is acceptable. Due to the IPC filtering the input, this display may toggle high without the CHECK COOLANT LEVEL message being displayed.

IPI10: Disregard. The FAST IDLE display is not available.

IPI12: The INTERIOR LAMPS display is low when the interior lamps switch is in the ON position.

IPI13: The HEADLAMP LOW BEAM display is low when the headlamp switch is in the ON position or when the low beams are ON due to the automatic low-beam-ON feature (e.g. the twilight sentinel, the wiper-activated headlamps).

IPI14: The PARK LAMPS display is low when the park lamps switch is in the ON position.

IPI15: The FRONT FOG LAMP display is low when the front fog lamp switch is in the ON position.

IPI16: The REAR FOG LAMP display is low when the rear fog lamp switch is in the ON position (Export only).

IPI17: The TWILIGHT ENABLE display is low when the twilight enable switch is in the OFF position.

IPI18: The FUEL DOOR RELEASE is low when the fuel door switch is pressed.

IPI19: The DRIVER INFO display is low when the INFO (analog) or INFORMATION (digital) switch is pressed.

IPI20: The TRIP RESET display is low when the TRIP RESET switch is pressed.

IPI21: The RESET display is low when the INFO RESET (analog) or RESET (digital) switch is pressed. Pressing this button exits the vehicle diagnostic system when active.

IPI24: The LEFT TURN SWITCH display is high when the left turn switch is ON and the output from the turn signal flasher module is ON.

IPI25: The RIGHT TURN SWITCH display is high when the right turn switch is ON and the output from the turn signal flasher module is ON.

IPC Override Displays

Important: If any of the override values are changed and the following procedure is not followed, DTC B1557 may be set. DTC B1557 may not be cleared. DTC B1557 is a non-recoverable condition. Replace the IPC if DTC B1557 is present. If the OFF button is pressed and the IPC displays the IPC CLEAR CODES message, exit the vehicle diagnostic system and start over. This action resets the override options back to the original values and prevents DTC B1557 from setting.

The current override value is displayed in the trip odometer display. Follow the procedure below in order to change the override value.

1. Add the value of the new feature (shown on the right) to the displayed override value.
2. Increment the value by pressing the appropriate button below:

•	Digital IPC -- the CCC warmer (RED) button

•	Analog IPC -- the CCP PASS warmer (up arrow) button

3. Decrement the value by pressing the appropriate button below:

•	Digital IPC -- the CCC cooler (BLUE) button

•	Analog IPC -- the CCP PASS cooler (down arrow) button

4. In order to permanently store the new value, press and hold the buttons below until the new displayed override value flashes once (approximately 5 seconds):

•	Digital IPC -- the front defrost (symbol) and the AUTO/ECON buttons

•	Analog IPC -- the front defrost (symbol) and the A/C buttons

IPS00: This test displays none. No overrides are active at this point.

IPS01: Option A:

IPS02: Option B (Export Country):

IPS03: Option C:

IPS04: Option D:

IPS05: Option E (driver message center display options):

Important: The assembly plant sets the digital IPCs to 122. The plant sets the analog IPCs to 43.

IPS06: This code allows the HVAC system set temperature to be different from the driver commanded (CCC or CCP) set temperature from -5°F to 5°F.

IPS07: This code allows the incandescent dimming (INC DIM 1) to be moved from OFF to full bright in order to inspect the lighting.

IPS08: This code allows the incandescent dimming (INC DIM 2) to be moved from OFF to full bright in order to inspect the lighting.

IPS09: This code allows the starter enable output to be overridden for up to 5 seconds in order to verify operation. The vehicle will not start unless the IPC PASSKey® II keyword and the PCM stored password match.

IPS10: The alternator disable output is not available. Changing the value has no effect on the IPC.

IPS11: The DE-ICE is not available.