Instrument Panel Cadillac DeVille Concours

DESCRIPTION & OPERATION

Instrument Panel Cluster (IPC) consists of either a digital cluster or an analog cluster. (Scheme 1)and (Scheme 2). IPC has capability to diagnose malfunctions in sensors, input switches, components and systems it controls or communicates with. When IPC, or another microprocessor-controlled module, detects a malfunction, it may turn on an IPC indicator or request/display a message to Driver Information Center (DIC) to alert driver that a malfunction has occurred. Some indicator lights and IPC messages have dual controls.

IPC contains 2 microprocessors as part of the instrument panel assembly. IPC can recognize operational malfunctions, alert driver through indicators or Driver Information Center (DIC) messages and store DTCs which identify malfunction areas.

Scheme 1

Scheme 2

AIR BAG PRECAUTIONS

The following precautions must be observed when working on vehicles equipped with Supplemental Inflatable Restraint (SIR) air bag systems

1. Before performing any instrument panel testing, diagnosis or repair, disable SIR system by disconnecting negative battery cable and Yellow 2-pin connectors at base of steering column and behind trap door in glove box.
2. Wait 20 minutes before making SIR repairs to enable SIR system Diagnostic Energy Reserve Module (DERM) to power down. DERM retains enough voltage to deploy air bag for a short time after battery voltage is disconnected.
3. To avoid accidental air bag deployment, avoid any Yellow SIR wiring harnesses when trouble shooting, repairing or replacing instrument panel components. All SIR wiring harnesses are color-coded Yellow.

HANDLING PRECAUTIONS

1. Discharge personal static electricity by momentarily touching metal grounding point on vehicle before coming in contact with electronic components.
2. NEVER touch terminals on components or connectors with fingers or metal tools. When disconnecting connectors, NEVER let metal tool contact any exposed terminal.
3. NEVER jumper, ground or use test meter probes on components or connectors unless specified in diagnostic procedures. Always connect ground lead first.
4. DO NOT remove solid-state components from protective packaging until ready for installation. Touch packaging to ground before opening.
5. DO NOT bump or drop component. DO NOT lay component on metal work bench, electrical metal objects or other electrically operated components, such as radio, TV or oscilloscope.

COMPONENT TESTING

Indicator Diagnosis

1. Battery voltage is applied to the BRAKE indicator when the ignition switch is in RUN, BULB TEST or START position. Ground for the circuit is supplied through any of several switches which monitor low brake fluid level, unequal brake pressure and parking brake lever engagement.
2. BRAKE indicator may also come on when a problem is detected in anti-lock brake system (if equipped). If there is a problem with BRAKE indicator functioning, check appropriate switches and circuits. See «WIRING DIAGRAM»(/cadillac/deville-concours/1994-1998/remont/gauges-instrument-panels/#instrument-panel) .

CRUISE CONTROL SWITCH TEST

For testing information on cruise control, see appropriate CRUISE CONTROL SYSTEM article.

HEADLIGHT SWITCH TEST (WITH TWILIGHT SENTINEL)

For testing information on Twilight Sentinel system, see HEADLIGHTS - AUTOMATIC TWILIGHT SENTINEL article.

OIL PRESSURE SWITCH TEST

1. Locate oil pressure switch at top of oil filter housing and disconnect connector. Using DVOM, with engine off, ensure continuity exists between switch terminal and switch ground. If continuity does not exist, replace switch.
2. With engine running at idle, continuity should not exist. If continuity exists with engine running, turn engine off immediately. Use manual oil pressure gauge tester to ensure oil pressure is greater than 5-10 psi at idle. If oil pressure is as specified, replace oil pressure switch.

SELF-DIAGNOSTIC SYSTEM DESCRIPTION

IPC is equipped with an extensive diagnostic system which is capable of detecting and compensating for malfunctions and alerting the driver of a malfunction.

Diagnostic Trouble Codes (DTCs)

Diagnostic Trouble Codes (DTCs), when set, indicate that IPC has detected a malfunction in a circuit or other system. IPC is programmed with routines for internal checks that it follows only when prescribed test conditions. When these conditions exist, IPC checks certain circuits or systems for a malfunction. These checks are called failure conditions. When a failure condition is present, a DTC is set. Some DTCs alert the driver through a Driver Information Center (DIC) message. Other DTCs do not trigger a driver warning. DTCs are not stored in the IPC EEPROM and are not retained after battery is disconnected.

Current DTC

When IPC determines that test conditions and failure conditions for a particular DTC are true, it sets that DTC as CURRENT. All DTCs remain current until the next time IPC finds test conditions are true and failure conditions are false. A few DTCs remain current until next ignition cycle or until failure conditions are false several times.

History DTC

After a DTC has been set, IPC continues to monitor for test and failure conditions. For most DTCs, if test conditions are true and failure conditions are false, DTC is changed to history. Some DTCs require test conditions to be true and failure false several times or require an ignition cycle to change from current to history. If there are no current DTCs for 50 ignition cycles, all history DTCs will be cleared.

Displaying DTCs

Turn ignition on. Press OFF and WARMER buttons of climate control center/panel until all segments of display are on. Driver Information Center (DIC) will display all DTCs set. Each DTC will be displayed along with its status, current or history. DTCs will display in following order: PCM, IPC, ACM, SDM, TCS, RSS, PZM, IRC, RFA, CCP, and PHN. This article only covers IPC codes. For information on other codes, see appropriate TESTS W/CODES article. Also see appropriate BODY CONTROL MODULE article. Pressing FAN DOWN button will bypass DTC display.

Erasing DTCs

IPC clear (erasing) codes option can be used to clear stored IPC DTCs. When selected, IPC clear codes option immediately erases all DTCs stored to that point and DIC displays IPC CODES CLEAR. Once a malfunction has been corrected, clear DTCs so future service is not duplicated.

Generator L-Terminal Open Circuit

1. Connect scan tool. Turn ignition on. Using scan tool, select IPC, DATA LIST, INPUTS, and ALT L TERMINAL. If scan tool does not display on, go to next step. If scan tool displays on, replace IPC.
2. Turn ignition off. Disconnect IPC connector C1. Disconnect generator. Measure resistance in Red wire between IPC connector C1 terminal A9 and generator terminal "L". If resistance is greater than 5 ohms, go to next step. If resistance is less than 5 ohms, repair open circuit in Red wire.
3. Reconnect IPC connector C1. Turn ignition on. Measure voltage between generator connector terminal "L" (Red wire) and ground. If about battery voltage is present, replace generator. If about battery voltage is not present, replace IPC.

Generator L-Terminal Fault Malfunction

1. This test is only performed when engine is running with an engine speed greater than 600 RPM and service diagnostics is not active.
2. Probe generator "L" terminal (Red wire) and check for battery voltage while engine is running. If battery voltage is present, check for an intermittent short or open circuit in Red wire. If battery voltage is not present, check for an open circuit in Red wire. If wire is okay, replace IPC.

Battery Voltage Too Low

1. Connect scan tool. Turn ignition off. Using scan tool, select DATA LIST, DATA. If battery voltage displayed on scan tool is 10 volts or less, go to next step. If battery voltage displayed on scan tool is not 10 volts or less, replace IPC.
2. Measure voltage between IPC connector C1 terminal A1 (Orange wire) and ground. If voltage is 10 volts or less, problem is in charging system. See appropriate «GENERATOR & REGULATOR»(/cadillac/deville-concours/1994-1998/remont/charging-system/#charging-system) article in ELECTRICAL section. If voltage is not 10 volts or less, replace IPC.

Battery Voltage Too High

1. Connect scan tool. Turn ignition off. Using scan tool, select DATA LIST, DATA. If battery voltage displayed on scan tool is 10 volts or less, go to next step. If voltage displayed on scan tool is 16 volts or more, go to next step. If voltage displayed on scan tool is not 16 volts or more, replace IPC.
2. Measure voltage between IPC connector C1, terminal A1 (Orange wire) and ground. If voltage is 16 volts or more, problem is in charging system. See «GENERATOR & REGULATOR»(/cadillac/deville-concours/1994-1998/remont/charging-system/#charging-system) article in ELECTRICAL section. If voltage is not 16 volts or more, replace IPC.

Loss Of PCM Data

1. DTC IP 2016 will set if ignition is on and IPC is not able to exchange data with PCM. If vehicle will not start, see appropriate «TESTS W/CODES»(/cadillac/deville-concours/1994-1998/remont/testing-diagnostics/#engine-control-system-tests-wcodes) article. If vehicle will start, go to next step.
2. Turn ignition off. Disconnect connector C205. Disconnect PCM connector C1. Measure resistance of Purple wire between connector C205 terminal "C" and PCM connector C1 terminal No. 59. If resistance is 5 ohms or less, go to next step. If resistance is more than 5 ohms, repair open circuit in Purple wire between PCM and connector C205.
3. Disconnect heater and A/C programmer connector. Measure resistance between programmer terminal D4 to connector C205 terminal "C" (Purple wire). If resistance is 5 ohms or less, repair open circuit in Purple wire. If resistance is more than 5 ohms. replace PCM.

Loss Of BCM Data

If Body Control Module (BCM) is not operating correctly, see appropriate BODY CONTROL MODULE article. If BCM is operating correctly, check for good terminal contact to BCM at connector C1 terminals A9 (Purple wire) and B9 (Purple wire). If terminal contact is okay, replace BCM.

Loss Of IRC Data

If radio is not functioning correctly, perform IRC DTC PZ2128 test in appropriate BODY CONTROL MODULE article. If radio is functioning correctly, check for good terminal contact to IRC at terminals E6 and F6 (Purple wires). If wires are okay, replace IRC.

Loss Of Heater & A/C Programmer Data

If Heater, Ventilation and Air Conditioning (HVAC) programmer is not operating correctly, see A/C-HEATER SYSTEM - AUTOMATIC article. If HVAC programmer is operating correctly, check for good terminal contact to HVAC programmer at terminals D2 and D4 (Purple wires).

Twilight Sentinel Photo Sensor Malfunction

1. Disconnect twilight photocell connector. Turn ignition on. Measure voltage between photocell harness connector terminal "A" (White wire) and ground. If voltage is not greater than 5 volts, go to next step. If voltage is greater than 5 volts, repair short circuit to voltage in White wire.
2. Turn ignition off. Measure resistance between twilight photocell terminal "A" (White wire) and ground. If resistance is not 6 ohms or less, go to next step. If resistance is 6 ohms or less, repair short to ground in White wire.
3. Measure resistance between twilight photocell terminal "B" (Black wire) and ground. If resistance is 5 ohms or less, replace IPC. If resistance is not 5 ohms or less, repair open circuit in Black wire.

DTC IP 2510

Note. Code sets if a HVAC switch is stuck for 12.5 seconds or more.

HVAC Steering Wheel Controls Stuck

If any steering wheel control switches are stuck, it may cause another switch not to function correctly. Check switch for binding, sticking, or broken steering wheel touch controls. If steering wheel is okay, clear DTC. Check condition of steering wheel controls. If DTC resets, replace steering wheel control switches.

DTC IP 2511

Note. Code sets if radio control switch is stuck for 5 seconds.

Convenience Key Steering Wheel Controls Stuck

Check for binding, sticking or broken steering wheel touch controls. If steering wheel touch controls are okay, clear DTC. Check operation of steering wheel controls. If DTC again sets, replace steering wheel control switches.

Incorrect Resistance Value In Steering Wheel Controls

Each steering wheel control switch has a unique resistance. These resistance values can be measured by disconnecting connector C202 and measuring with an ohmmeter between terminals A1 (Yellow wire) and A4 (No Color Available). Close switch being tested. Keys are labeled according to installed options. See STEERING WHEEL CONTROL RESISTANCE table.

STEERING WHEEL CONTROL RESISTANCE

PASS-KEY II Malfunctions

PASS-KEY II system uses a resistor pellet with 15 different potential values in vehicle ignition key. When key is inserted into ignition key cylinder, pellet value is read and compared to 3 vehicle specific key values stored in memory. Result of this comparison is used to determine whether or not to allow vehicle starting and to also display system status messages. Displayed messages indicate whether a valid or invalid key pellet value has bee detected or if there is a problem with the key pellet read circuitry. If a valid code is detected, IPC will send a class 2 serial data bus password message, along with a request to enable fuel, to PCM. PCM must recognize password by checking against 3 values stored in EEPROM before fuel is enabled. IPC will not energize starter enable relay until PCM responds with vehicle status report acknowledgment to password message. Any deviation in the sequence will result in a DTC.

PASS-KEY II Open/Shorted Key Pellet

1. Put ignition key in ignition lock cylinder. Disconnect connector at base of steering column. Measure resistance between connector terminals "E12" (White/Black wire) and "E13" (Purple/White wire). If resistance is not less than 20 ohms, go to next step. If resistance is less than 20 ohms, remove ignition key. Measure resistance between same terminals as previously measured. If circuit is open, replace key. If circuit is not open, replace ignition lock cylinder.
2. If resistance is not less than 11.8 k/ohms, go to next step. If resistance is 11.8 k/ohms or more, insert other key. Measure resistance between terminals measured in step 1). If resistance is greater than 11.8 k/ohms, replace ignition lock cylinder. If resistance is not greater than 11.8 k/ohms, replace key.
3. Disconnect Instrument Panel Cluster (IPC) connector C1. Measure resistance between IPC connector C1 terminals A10 (White/Black wire) and B10 (Purple/White wire). If resistance is not 5 ohms or less, go to next step. If resistance is 5 ohms or less, repair short from White/Black wire to Purple/White wire.
4. Measure resistance between IPC connector C1 terminal A10 (White/Black wire) and ground. If resistance is not 5 ohms or less, go to next step. If resistance is 5 ohms or less, repair short from White/Black wire to ground.
5. Measure resistance between IPC connector C1 terminal B10 (Purple/White wire) and ground. If resistance is 5 ohms or less, repair short circuit from Purple/White wire to ground. If resistance is not 5 ohms or less, replace IPC.

PASS-KEY II Data Communication Failure

1. Turn ignition on. Wait one minute. If DTC 2750 is current, go to next step. If DTC 2750 is not current (history), it is possible an intermittent condition is present. Check for DTC 2016 or 2255. If other DTCs are present, verify PCM power, ground, and serial data connections.
2. If PRNDL is boxed and flashing, go to next step. If PRNDL is not boxed and flashing, determine whether IPC or PCM have been swapped in this vehicle. If IPC or PCM have been swapped, perform PASS-KEY II relearn. See appropriate «ANTI-THEFT SYSTEM»(/cadillac/deville-concours/1994-1998/remont/door-locks-anti-theft-systems/#anti-theft-system) article. If IPC or PCM have not been swapped, replace PCM.
3. Attempt to establish communications with PCM using on-board diagnostics. If NO DATA is not displayed, go to next step. If NO DATA is displayed, verify PCM operation, power, ground and serial data connections.
4. If a PCM 1520 current DTC is set, go to next step. If a PCM 1520 current DTC is not set, an intermittent condition exists on class 2 serial data line. Perform diagnosis/repair as a DTC IP 2016.
5. If IPC or PCM have been replaced, perform a PASS-KEY II relearn using scan tool. See appropriate «ANTI-THEFT SYSTEM»(/cadillac/deville-concours/1994-1998/remont/door-locks-anti-theft-systems/#anti-theft-system) article. If IPC or PCM have not been replaced, replace PCM.

PASS-KEY II Wrong Resistor Value Before Good

1. Ensure key is clean and free from contamination. Put key in ignition switch. Crank engine. If STARTING DISABLED is displayed, go to next step. If STARTING DISABLED is not displayed, replace key.
2. Wait 3 minutes then place another valid key in ignition. Crank engine. If STARTING DISABLED is not displayed, replace key. If STARTING DISABLED is displayed, use Interrogator (J 35628) to determine whether any pellet matches that stored in IPC. If any of 15 do not match, replace IPC. If any of 15 do match, reprogram PASS-KEY II system. See appropriate «ANTI-THEFT SYSTEM»(/cadillac/deville-concours/1994-1998/remont/door-locks-anti-theft-systems/#anti-theft-system) article. If DTC 2780 is still current, replace IPC.

Wrong Resistor Value After Good

1. Using Interrogator (J 35628), measure resistance of original key and determine whether it falls within a valid resistance range. See appropriate «ANTI-THEFT SYSTEM»(/cadillac/deville-concours/1994-1998/remont/door-locks-anti-theft-systems/#anti-theft-system) article. If resistance is not within range, replace key. If resistance is within range, go to next step.
2. Turn ignition on. Wait 30 seconds. If DTC 2701 is current, go to next step. If DTC 2701 is not current, check key for pellet damage. Replace as necessary.
3. Insert a valid key into ignition cylinder and turn switch to RUN position. Wait 30 seconds. If code is not current, replace key. If code is current, turn ignition off. Disconnect IPC connector C1. Measure resistance between terminals A10 (White/Black wire) and B10 (Purple/White wire).
4. If measured resistance is within 20 ohms of original pellet resistance and still in a valid resistance range, replace IPC. If measured resistance is not within 20 ohms of original pellet resistance and is not within a valid resistance range, check White/Black and Purple/Black wires for an open or short circuit.

Pellet Not Programmed

Insert another valid key and cycle ignition switch from OFF to RUN positions. If DTC IP 2782 is current, replace key. If DTC IP 2782 is not current, replace IPC.

Key Code/Password Corrupted

This DTC indicates that all 3 key codes or passwords stored in EEPROM do not match one another, or are all ones or all zeros. There is no other message associated with this problem. A faulty DTC is the only probable cause if this is the only DTC. If other DTCs exist, diagnose other DTCs first.

Removal & Installation

1. Remove A5-IPC and B5-IPC fuses from rear compartment fuse panel. Remove fuse A3-IGN1 from engine compartment fuse panel. Use a small, flat-bladed tool and pry upward on defroster grille. Remove sunload and headlight auto control sensor from defroster grille. Working through defroster grille opening, remove 3 screws retaining upper trim panel.
2. Remove 4 heat and A/C vents from front of instrument panel by releasing tab inside vent and pulling outward. Remove 4 screws retaining upper trim panel through vent openings. On Concours and DeVille, on passenger side of vehicle, press down on forward edge of trim panel while pulling upward and back on rear edge of panel. On Seville, pull upward and back on rear edge of trim panel. On all models, remove upper trim panel.
3. Disconnect 2 electrical connectors on top of instrument panel cluster. Remove 4 instrument cluster-to-instrument panel screws. Remove steering column opening bracket. Remove instrument panel cluster.

These 2 units are integral components of instrument cluster. If either unit must be replaced, replace complete instrument cluster assembly. See INSTRUMENT PANEL CLUSTER .

Remove headlight switch module from instrument panel by carefully, yet firmly, pulling outward on switch knob while prying on module's opposite side to remove switch from panel. (Scheme 3) Disconnect both wiring connector retaining clips. Carefully pull connectors straight back away from switch pins. Remove switch. To install, reverse removal procedure.

Scheme 3

1. Remove A5-IPC and B5-IPC fuses from rear compartment fuse panel. Remove fuse A3-IGN1 from engine compartment fuse panel. Use a small, flat-bladed tool and pry upward on defroster grille. Remove sunload and headlight auto control sensor from defroster grille. Working through defroster grille opening, remove 3 screws retaining upper trim panel.
2. Remove 4 heat and A/C vents from front of instrument panel by releasing tab inside vent and pulling outward. Remove 4 screws retaining upper trim panel through vent openings. On Concours and DeVille, on passenger side of vehicle, press down on forward edge of trim panel while pulling upward and back on rear edge of panel. On Seville, pull upward and back on rear edge of trim panel. On all models, remove upper trim panel.
3. Disconnect 2 electrical connectors on top of instrument panel cluster. Remove 4 instrument cluster-to-instrument panel screws. Remove steering column opening bracket. Remove instrument panel cluster.

1. Raise long defroster grille by carefully prying upward using small, flat-blade screwdriver. (Scheme 4) Depending on interior trim, sunload sensor and twilight sentinel photocell may need to be removed from bottom of defroster grille, before removing grille from vehicle. (Scheme 5)
2. Remove 3 top cover retaining screws from inside defroster grille opening. Remove A/C vent outlet grilles from front of panel by gently prying inward on each side of grille to release retaining tabs. Pull grilles straight out from panel openings.
3. Remove 4 top cover retaining screws from inside grille openings. Remove top cover from instrument panel using care not to scratch windshield pillars. To install, reverse removal procedure.

Scheme 4

Scheme 5

1. Remove left sound insulator from left lower instrument panel, underneath steering column. Remove steering column opening trim by pulling downward away from slots in steering column opening bracket. (Scheme 6)
2. Remove 4 retaining screws from steering column opening bracket and remove. Locate turn signal or hazard flasher unit. see scheme 8 Disconnect harness connector and remove desired unit. To install, reverse removal procedure.

Scheme 6

Scheme 7

See also:
• COMPUTER RELEARN PROCEDURES
• CRUISE CONTROL SYSTEM
• HEADLIGHTS - AUTOMATIC TWILIGHT SENTINEL
• TESTS W/CODES
• BODY CONTROL MODULE
• GENERATOR & REGULATOR
• A/C-HEATER SYSTEM - AUTOMATIC
• ANTI-THEFT SYSTEM
• WIRING DIAGRAM