Body Control Modules Cadillac DeVille Concours I final

DESCRIPTION & OPERATION

Note. Body Control Module (BCM) may also be referred to as Platform Zone Module (PZM).

The Platform Zone Module (PZM) performs the following functions: HVAC afterblow control, battery guard, door lock and unlock, fuel level, retained accessory power, theft deterrent, exterior and interior lighting control, trunk release, time of day for radio display, rear defog, fuel door release, and vehicle personalization.

Signals that activate the PZM are known as "wake-up" signals. PZM is asleep when it is not controlling or monitoring the following wake-up functions: Key in door lock switch, door ajar switches, power door lock switches, trunk ajar switch, trunk tamper switch, ignition on, ignition accessory (ACC), and any class 2 communication requiring PZM interaction.

PZM uses class 2 serial data line to communicate with other system control modules. Class 2 serial data is transmitted on a single wire at an average of 10.4 Kbps (10,400 bits per second). Class 2 uses a variable pulse width modulation to carry data, and speed is determined by message being transmitted. The bus is active at 7 volts nominal and inactive at ground potential. Class 2 serial data line is tolerant to different levels of ground potential.

COMPONENT LOCATIONS

COMPONENT LOCATIONS

Scheme 1

SELF-DIAGNOSTIC SYSTEM

Note. Body Control Module (BCM) may also be referred to as Platform Zone Module (PZM).

Note. Vehicles with analog instrument panel cluster are equipped with a Climate Control Panel (CCP). Vehicles with digital instrument panel cluster are equipped with a Climate Control Center (CCC). References to CCP also include CCC. CCC and CCP may be referred to as A/C-heater control panel.

Platform Zone Module (PZM) is equipped with a self-diagnostic system, which detects system failures or abnormalities. When a malfunction occurs, PZM will store a 5-digit alphanumeric Diagnostic Trouble Code (DTC).

After PZM DTCs have been displayed, service mode can be used to clear DTCs and exit diagnostics or individually perform other tests on different systems. To exit diagnostic mode, press DEFOG or MODE button on CCP, or turn ignition off. DTCs will not be cleared. System will return to normal vehicle operation.

RETRIEVING & CLEARING DIAGNOSTIC TROUBLE CODES (DTCs)

Note. If vehicle is to be operated in diagnostics without engine running for an extended time period, use battery charger to prevent battery from running down or system setting false diagnostic information.

Note. PCM, IPC, ACM, SDM, TCS, CVRSS, IRC, RFA, CCP and PHN systems can also be tested in service mode. Only information related to Platform Zone Module (PZM) diagnosis is covered in this article.

Climate Control Panel (CCP) is used to display PZM information while in diagnostic mode. CCP displays Diagnostic Trouble Codes (DTCs) for Powertrain Control Module (PCM), Instrument Panel Cluster (IPC), Air Control Module (ACM), Sensing and Diagnostic Module (SDM), Electronic Brake and Traction Control Module (EBTCM), Continuously Variable Road Sensing Suspension (CVRSS), Platform Zone Module (PZM), Integrated Radio Controller (IRC), Remote Function Actuator (RFA), Climate Control Panel (CCP), and Cellular Telephone (PHN).

Retrieving DTCs

To retrieve DTCs using scan tool, select PZM data on scan tool. Select DTC function for PZM. Select HISTORY or CURRENT DTC display function to view corresponding codes.

To enter diagnostic mode using on-board diagnostics, turn ignition on. Simultaneously press OFF and WARMER (Red bar) buttons on climate control center (digital instrument panel), or OFF and PASSENGER WARMER on climate control panel (analog instrument panel). Pressing LO (fan speed) button will scroll through modules available. Scroll through until PZM? appears. Pressing HI (fan speed) button will scroll through functions of selected module (i.e., PZM DATA, PZM INPUTS, PZM OUTPUTS, etc.). Scroll through until PZM CODES? appears. Press HI (fan speed) button until all PZM DTCs appear. Note codes and go to PZM DTC DEFINITIONS . To exit diagnostic mode, press DEFOG or MODE button on CCP, or turn ignition off. DTCs will not be cleared. System will return to normal vehicle operation.

Clearing DTCs

To clear DTCs using scan tool, select PZM data on scan tool. Select DTC function for PZM. Select CLEAR CODES function. When prompted, select YES to clear codes.

To clear DTCs using on-board diagnostics, turn ignition on. Simultaneously press OFF and WARMER (Red bar) buttons on climate control center (digital instrument panel), or OFF and PASSENGER WARMER on climate control panel (analog instrument panel). Press LO (fan speed) button until PZM? appears. Press HI (fan speed) button until PZM CODES? appears. Press LO (fan speed) button until PZM CODES CLEAR appears. Press HI (fan speed) button until all PZM CODES CLEAR appears. To exit clear codes mode, press DEFOG or MODE button on CCP, or turn ignition off. If mode is exited before DTCs are cleared, DTCs will not be cleared. System will return to normal vehicle operation.

PZM COMMUNICATION PROBLEMS

PZM DTC DEFINITIONS

DIAGNOSTIC PARAMETERS

Note. For reference during diagnostics (Scheme 2)and (Scheme 3).

PZM Data Values

PZM data selection provides display of actual analog value as indicated by system.

PZM Input Values

PZM input selection provides testing of inputs to PZM. Input status is shown on display as HI or LO. Input test status is shown as "O" until PZM sees a transition in state of switch; status then changes from "O" to "X". This changing status can be monitored to check inputs.

PZM Output Values

PZM output selection provides ability to check if PZM-controlled outputs can be actuated regardless of inputs or normal program instructions. When an output test is selected, test will display HI and LO for 3 seconds in each state to indicate command and output terminal voltage.

PZM Overrides

PZM override selection provides testing of certain system functions regardless of normal program instructions, as long as test conditions are met. When a test is selected, current mode of function will be displayed as a percentage on Driver Information Center (DIC). If test conditions are not met, DIC will display "==" instead of override value selected.

DIC display will alternate between "--" and normal programmed command. On vehicles with digital instrument panel, pressing WARMER button (Red bar) will increase override value and pressing COOLER button (Blue bar) will decrease override value. On vehicles with analog instrument panel, pressing PASSENGER WARMER button will increase override value and pressing PASSENGER COOLER button will decrease override value.

On all models, upon release of button, display may either remain at overridden value or automatically return to normal program control, depending on which function is being overridden. If value remains in override state, normal program control can be resumed by selecting another override test, selecting another system, or overriding value beyond either extreme of zero or 99. If override value is beyond an extreme value, display will alternate between "--" and opposite extreme value. Pressing button when "--" is displayed will return system to normal program control and display will again alternate.

When an override test is commanded, its effect on any DATA or INPUT test for that selected system may be observed. After selecting an override test, pressing OFF button will allow another test type to be selected (selected override value will continue to be displayed). On vehicles with digital instrument panels, select desired DATA or INPUT test, then use WARMER (Red bar) or COOLER (Blue bar) buttons to monitor effect of override value on displayed data or input. On vehicles with analog instrument panels, select desired DATA or INPUT test, then use PASSENGER WARMER or COOLER button to monitor effect of override value on displayed data or input.

Scheme 2

Scheme 3

Note. To locate components, go to COMPONENT LOCATIONS . For wiring and connector terminal identification, see WIRING DIAGRAMS. To identify wire colors and components on class 2 serial data line, see appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING DIAGRAMS.

BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK

Note. Use adapter from Terminal Test Adapter Kit (J-35616-A) connected to DVOM when making all measurements.

1. Connect scan tool to DLC. Turn ignition on. Attempt to establish communications with Platform Zone Module (PZM). If scan tool communicates with vehicle, go to next step. If scan tool does not communicate with vehicle, go to step 3 .
2. Select DISPLAY PZM DTC function on scan tool. If any DTCs are set, go to appropriate diagnosis and repair procedure. If no DTCs are set, system is okay at this time.
3. Attempt to establish communications with other systems on the class 2 data line. If scan tool communicates with other systems, go to next step. If scan tool does not communicate with other systems along the class 2 data line, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
4. Turn ignition off. Disconnect PZM connectors C-1 and C-2. Turn ignition on. Use DVOM to measure voltage between ground and PZM power circuits. See «WIRING DIAGRAMS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . If reading is 10-15 volts, go to next step. If reading is not 10-15 volts, go to step 7 .
5. Use DVOM to measure voltage between battery voltage and PZM ground circuits. If reading is 10-15 volts, go to next step. If reading is not 10-15 volts, go to step 8 .
6. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . After replacement, go to step 9 .
7. Repair open or short to ground in PZM power circuit. After repairs, go to step 9 .
8. Repair open in PZM ground circuit. After repairs, go to step 9 .
9. Turn ignition off. Reconnect all disconnected components and connectors. Use DVOM to clear all DTCs. If DTCs do not reset, system is okay at this time. If DTCs reset, go to step 2 .

DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK

1. Connect scan tool. Turn ignition switch to ON position. Attempt to establish communication with Platform Zone Module (PZM). If communication cannot be established, go to next step. If communication can be established, go to next step. If communications cannot be established, go to «DATA LINK COMMUNICATIONS SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-system-check) .
2. Check for communication DTCs. Communication DTCs begin with "U" (example - Uxxxx). If any communication DTCs are set, go to appropriate diagnostic and repair procedure. If no communication DTCs are set, system is okay at this time.

DATA LINK COMMUNICATIONS SYSTEM CHECK

Using scan tool, attempt to establish communication with another system on class 2 serial data line. Scan tool should turn on and communicate with other class 2 devices. If communication cannot be established, go to SCAN TOOL WILL NOT COMMUNICATE WITH CLASS 2 SERIAL DATA .

SCAN TOOL WILL NOT COMMUNICATE WITH CLASS 2 SERIAL DATA

1. Perform «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) . Go to next step.
2. Connect scan tool to another 1999 model year vehicle to ensure proper operation of scan tool. If scan tool operates on another vehicle, go to step 4 . If scan tool does not operate, go to next step.
3. Refer to scan tool manufacture's instructions for proper operation. After repairing scan tool, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
4. Connect scan tool to malfunctioning vehicle. Check connections between DLC and scan tool connector. If connections are okay, go to step 6 . If connections are faulty, go to next step.
5. Repair terminal contact between DLC and scan tool. After repairs, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
6. Turn ignition on. If scan tool powers up, go to step 12 . If scan tool does not power up, go to next step.
7. Use DVOM to measure voltage between ground and DLC terminal No. 16 (Orange wire). See «WIRING DIAGRAMS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . If reading is 10-15 volts, go to step 9 . If reading is not 10-15 volts, go to next step.
8. Repair open or short to ground in Orange wire between fuse block and DLC. After repairs, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
9. Use DVOM to measure voltage between DLC terminals No. 16 (Orange wire) and No. 5 (Black/White wire). If reading is 10-15 volts, go to step 11 . If reading is not 10-15 volts, go to next step.
10. Repair open in Black/White wire between ground and DLC. After repairs, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
11. Disconnect PCM connectors. Attempt to communicate with Body Control Module (PZM). If scan tool communicates, go to next step. If scan tool does not communicate, go to step 13 .
12. Replace PCM. See REMOVAL, OVERHAUL & INSTALLATION - CARS article in ENGINE PERFORMANCE. After replacement, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
13. Disconnect EBTCM connectors. Attempt to communicate with PZM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step 16 .
14. Check for short to ground or short to battery voltage in Purple wire between EBTCM connector terminal No. 10 and PCM connector C1 terminal No. 58. If short was found, go to step 54 . If circuit is okay, go to next step.
15. Replace EBTCM. See appropriate ANTI-LOCK BRAKES article in BRAKES. After replacement, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
16. Disconnect radio connector. Attempt to communicate with PZM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step 18 .
17. Replace radio. After replacement, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
18. Disconnect Instrument Panel Cluster (IPC) connector. Attempt to communicate with PZM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step 20 .
19. Replace IPC. See ANALOG & ELECTRONIC INSTRUMENT PANELS - DEVILLE & ELDORADO article. After replacement, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
20. If vehicle is equipped with D55 (front floor console), go to next step. If vehicle is not equipped with D55, go to step 24 .
21. Disconnect A/C-heater control panel. Attempt to communicate with PZM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step 24 .
22. Check for short to ground or short to battery voltage in Purple wire between A/C-heater control panel connector terminal A8 and IPC connector C3 terminal D1. If short was found, go to step 54 . If circuit is okay, go to next step.
23. Replace A/C-heater control panel. See appropriate AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING. After replacement, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
24. If vehicle is equipped with A45 (Memory Personalization Package), go to next step. If vehicle is not equipped with A45, go to step 28 .
25. Disconnect Memory Mirror Module (MMM) connector. Module is located under left side of instrument panel above brake pedal. Attempt to communicate with PZM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step 28 .
26. Check for short to ground or short to battery voltage in Purple wire between MMM connector C1 terminal E16 and IPC connector C3 terminal D1 (without D55) or A/C-heater control panel connector terminal A8 (with D55). If short was found, go to step 54 . If circuit is okay, go to next step.
27. Replace MSM. After replacement, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
28. Disconnect A/C-heater programmer. Programmer is located behind the glove box. Attempt to communicate with PZM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step 30 .
29. Check for short to ground or short to battery voltage in Purple wire between A/C-heater programmer connector C2 terminal D2 and one of the following components: MMM connector C1 terminals F16 (with A45). A/C-heater control panel connector terminal B8 (with D55 and without A45). IPC connector C3 terminal D1 (without A45 and D55). If short was found, go to step 54 . If circuit is okay, go to step 55 .
30. If vehicle is equipped with factory cellular telephone, go to next step. If vehicle is equipped with aftermarket cellular telephone or has no telephone at all, go to step 33 .
31. Disconnect cellular telephone module connector. Module is located in center console. Attempt to communicate with PZM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step 33 .
32. Replace cellular telephone module. After replacement, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
33. If vehicle is equipped with A45 (Memory Personalization Package), go to next step. If vehicle is not equipped with A45, go to step 36 .
34. Disconnect Memory Seat Module (MSM) connector. Module is located under driver's seat. Attempt to communicate with PZM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step 36 .
35. Check for short to ground or short to battery voltage in Purple wire between MSM connector C1 terminal No. 26 and radio connector terminal E6. If short was found, go to step 54 . If circuit is okay, go to step 56 .
36. Disconnect Sensing and Diagnostic Module (SDM) connector. Module is located under passenger's seat. Attempt to communicate with PZM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step 39 .
37. Check for short to ground or short to battery voltage in Purple wire between SDM connector terminal No. 17 and one or more of the following components: MSM connector C1 terminal No. 25 (without A45). Radio connector terminal E6 (with A45). If short was found, go to step 54 . If circuit is okay, go to next step.
38. Replace SDM. See AIR BAG SERVICE & REPAIR MANUAL. After replacement, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
39. If vehicle is equipped with F45 (Real Time Dampening), go to next step. If vehicle is not equipped with F45, go to step 42 .
40. Disconnect Continuous Variable Road Sensing Suspension (CVRSS) module connector. Module is located behind rear seat back on right side. Attempt to communicate with PZM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step 42 .
41. Replace CVRSS module. After replacement, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
42. If vehicle is equipped with UQ4 (4-speaker Bose system) or UQ6 (11-speaker Bose system with amplifier), go to next step. If vehicle is not equipped with UQ4 or UQ6, go to step 47 .
43. Disconnect radio amplifier (DeVille) or the Radio Interface Module (RIM - Eldorado). Both the amplifier and the module are located behind the rear seat back in the center. Attempt to communicate with PZM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step 47 .
44. If vehicle is equipped with F45 (Real Time Dampening), go to next step. If vehicle is not equipped with F45, go to step 47 .
45. Check for short to ground or short to battery voltage in Purple wire between CVRSS module connector C1 terminal D5 and one or more of the following components: Radio amplifier connector C1 terminal B2 (DeVille). RIM connector C1 terminal B2 (Eldorado). If short was found, go to step 54 . If circuit is okay, go to next step.
46. Replace radio amplifier (DeVille) or replace the RIM (Eldorado). After replacement, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
47. Disconnect the Remote Function Actuator (RFA). RFA is located behind center of rear seat back. Attempt to communicate with PZM. If scan tool communicates, go to next step. If scan tool does not communicate, go to step 51 .
48. If vehicle is equipped with F45, UQ4 or UQ6, go to next step. If vehicle is not equipped with F45, UQ4 or UQ6, go to step 50 .
49. Check for short to ground or short to battery voltage in Purple wire between RFA module connector terminal No. 2 and one or more of the following components: CVRSS module connector C1 terminal D5 (with F45 and without UQ4 or UQ6). Radio amplifier connector C1 terminal B3 (DeVille). RIM connector C1 terminal B3 (Eldorado). If short was found, go to step 54 . If circuit is okay, go to next step.
50. Replace RFA module. After replacement, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
51. Reconnect IPC connector. Disconnect PZM connector. Attempt to communicate with IPC. If scan tool communicates, go to next step. If scan tool does not communicate, go to step 54 .
52. Check for short to ground or short to battery voltage in Purple wire between PZM connector C1 terminal A2 and RFA module connector terminal No. 3. If short was found, go to step 54 . If circuit is okay, go to next step.
53. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . After replacement, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
54. Repair open, short to ground or short to battery voltage in Purple wire. After repairs, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
55. Replace A/C-heater control panel. See appropriate AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING. After replacement, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .
56. Replace MSM. See appropriate POWER SEATS article. After replacement, go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) .

Description

Platform Zone Module (PZM) monitors fuel level, and transmits this information over class 2 serial data line to Powertrain Control Module (PCM) and Instrument Panel Cluster (IPC). When ignition switch is in RUN position, PZM continually measures voltage at Brown 24-pin connector C1, terminal B12 (Purple/White wire) and determines position of sensor by calculating percentage of IGN-1 voltage present at terminal.

DTC B0532 will set if percentage of IGN-1 voltage at PZM Brown 24-pin connector C1, terminal B12 (Purple/White wire) is less than an acceptable level for at least 2 seconds. PZM will send a class 2 message to PCM that percentage of IGN-1 voltage is too low. DTC B0532 will clear if percentage of IGN-1 voltage meets or exceeds an acceptable level for at least one cycle.

Note. If DTC B1982 or B1983 is current, DTC B0532 will not be set, but a class 2 message will be sent to PCM that percentage of IGN-1 voltage is too low.

Testing

1. Check for short to ground in Purple/White wire between PZM and fuel level sensor. Repair as necessary. If circuit is okay, go to next step.
2. If DTC B0532 is current, replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. If DTC B0532 is history, replace fuel level sensor.

Platform Zone Module (PZM) monitors fuel level, and transmits this information over class 2 serial data line to Powertrain Control Module (PCM) and Instrument Panel Cluster (IPC). When ignition switch is in RUN position, PZM continually measures voltage at Brown 24-pin connector C1, terminal B12 (Purple/White wire) and determines position of sensor by calculating percentage of IGN-1 voltage present at terminal.

DTC B0533 will set if percentage of IGN-1 voltage at PZM Brown 24-pin connector C1, terminal B12 (Purple/White wire) is greater than an acceptable level for at least 2 seconds. PZM will send a class 2 message to PCM that percentage of IGN-1 voltage is too high. DTC B0533 will clear if percentage of IGN-1 voltage is less than or equal to an acceptable level for at least one cycle.

Note. If DTC B1982 or B1983 is current, DTC B0533 will not be set, but a class 2 message will be sent to PCM that percentage of IGN-1 voltage is too high.

1. Check for short to battery in Purple/White wire between PZM and fuel level sensor. Repair as necessary. If circuit is okay, go to next step.
2. If DTC B0533 is current, replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. If DTC B0533 is history, replace fuel level sensor.

DTC B1552 indicates keep alive memory (long term memory) of Platform Zone Module (PZM) has been reset. Keep alive memory will reset when power or ground is removed from PZM. This is a normal occurrence when battery is disconnected and reconnected. When DTC B1552 is set, PZM memory is reset to initial values. PZM will initialize keep alive memory contents to default the following

1. Fuel Level Empty
2. Afterblow Mode Disable
3. Afterblow Alarm Disable
4. Controlled Power Timer Set To Full Time
5. Power Down Hours Clear
6. Storage Mode State Disable
7. Key Cylinder State Inactive
8. Driver Door Jamb Closed
9. Other Door Jambs Closed
10. Ignition State Current State

1. Perform «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Turn ignition on. Clear DTCs with scan tool. Turn ignition off and back on. If DTC resets, go to next step. If DTC does not reset, go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.
3. Check for open in power and ground circuits of PZM. See «WIRING DIAGRAMS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . If open is found, go to next step. If circuit is okay, go to step 5 .
4. Repair open in power or ground circuit. After repairs, go to step 6 .
5. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After replacement, go to next step.
6. Turn ignition off. Reconnect all disconnected components and connectors. Turn ignition on and use scan tool to clear DTCs. Go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.

DTC B1556 testing is run for each write or block of writes to Electronically Erasable Programmable Read Only Memory (EEPROM). Platform Zone Module (PZM) writes to EEPROM cell and then reads data back. DTC B1556 will set when data read by PZM does not match data written to EEPROM after 2 consecutive attempts. DTC B1556 will clear when data read by PZM matches data written to EEPROM.

1. Perform «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Turn ignition on. Clear DTCs with scan tool. Turn ignition off and back on. If DTC resets, go to next step. If DTC does not reset, go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.
3. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After repairs, go to next step.
4. Turn ignition off. Reconnect all disconnected components and connectors. Turn ignition on and use scan tool to clear DTCs. Go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.

At beginning of ignition cycle, Platform Zone Module (PZM) adds the checksum of Electronically Erasable Programmable Read Only Memory (EEPROM) block and that block's twos complement. DTC B1558 will set when value of addition does not equal zero. When DTC B1558 is set, PZM will clear all codes, set DTC B1558 as current and default to the following

1. Personalization Factory Default
2. Ignition Cycle Counter Zero
3. Theft Alarm Condition Cleared

1. Perform «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Turn ignition on. Clear DTCs with scan tool. Turn ignition off and back on. If DTC resets, go to next step. If DTC does not reset, go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.
3. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After repairs, go to next step.
4. Turn ignition off. Reconnect all disconnected components and connectors. Turn ignition on and use scan tool to clear DTCs. Go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.

When exterior lights are requested, Platform Zone Module (PZM) commands exterior lights on by energizing headlight and parking light relays. DTC B1970 will set when exterior lights have been commanded on, but PZM senses exterior light power is low for 2 consecutive monitoring cycles. When DTC B1970 is set, PZM will command exterior lights off, then attempt to turn exterior lights on until lights are no longer required. DTC B1970 will clear when exterior lights are commanded on and PZM senses exterior light power on after 2 consecutive monitoring cycles.

1. Turn ignition switch to OFF position. Remove parking light relay and headlight relay. See «COMPONENT LOCATIONS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__component-locations) . Disconnect PZM connectors. Using DVOM, check resistance between ground and parking light relay terminal A6 (White wire) at trunk compartment relay center No. 5. See «WIRING DIAGRAMS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . If resistance is 5 ohms or less, go to step 3 . If resistance is greater than 5 ohms, go to next step.
2. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION.
3. Repair short to ground in White wire between parking light relay and PZM. Reconnect all components. Turn ignition switch to ON position. Turn headlights on. If headlights do not come on, go to step 2 . If headlights come on, system is functioning normally.

When Platform Zone Module (PZM) grounds inadvertent power relay, inadvertent power is commanded on and off. Battery voltage is supplied to components powered by inadvertent power relay when relay is energized.

DTC B1971 will set when inadvertent power relay is commanded on or off and PZM feedback state does not match commanded state for at least 2 seconds. When DTC B1971 is set, PZM will continue to command requested state of relay until it is achieved or no longer necessary. DTC B1971 will clear when PZM feedback state matches commanded state for at least 2 seconds.

1. Turn ignition switch to OFF position. Connect scan tool and select BCM TEST. Select INADV. POWER. Turn inadvertent power on. Turn interior lights on. If interior lights come on, go to step 3 . If interior lights do not come on, go to next step.
2. Remove inadvertent power relay. Disconnect PZM connectors. See «COMPONENT LOCATIONS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__component-locations) . Using DVOM, measure resistance between inadvertent power relay terminal C2 (Brown wire) and ground. See «WIRING DIAGRAMS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . If resistance is 5 ohms or less, go to step 4 . If resistance is greater than 5 ohms, go to step 5 .
3. Using DVOM, measure voltage between inadvertent power relay terminal A1 (Orange wire) and ground. If battery voltage exists, go to step 6 . If battery power does not exist, go to step 7 .
4. Repair short to ground in Brown wire between PZM and inadvertent power relay. After repairs, recheck operation of interior lights.
5. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After repairs, recheck operation of interior lights.
6. Use scan tool to command inadvertent power relay ON. Use DVOM to measure resistance between inadvertent power relay connector terminal C2 (Brown wire) and ground. If resistance is 5 ohms or less, go to step 8 . If resistance is greater than 5 ohms, go to step 9 .
7. Repair open or short to ground in Orange wire between inadvertent power relay and engine compartment fuse/relay center. After repairs, recheck operation of interior lights.
8. Replace inadvertent power relay. After repairs, recheck operation of interior lights.
9. Check for open in Brown wire between inadvertent power relay and PZM. If open is found, go to next step. If circuit is okay, go to step 5 .
10. Repair suspect wiring. After repairs, recheck operation of interior lights.

Controlled power relay supplies power to modules during controlled power usage. Whenever Platform Zone Module (PZM) is awake and ignition switch has been in LOCK position for 15 minutes or less, high power control output is grounded. After 15 minutes, low power control output is turned on. Low power control output will supply up to 2 amps of current for up to 72 hours. If PZM detects more than 2 amps of current is needed, PZM will wake-up and turn on high power control output.

DTC B1972 will set when low power control output is low after 2 consecutive monitoring cycles. When DTC B1972 is set, PZM will turn low power control output off until ignition state changes or PZM wakes up. DTC B1972 will clear when ignition state changes or PZM wakes up.

1. Perform «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Turn ignition switch to OFF position. Disconnect PZM connectors. Remove PZM fuse (10-amp) located in trunk compartment fuse block. Using DVOM, measure resistance between PZM Brown 32-pin connector C2 terminal C2 (Orange wire) and ground. See «WIRING DIAGRAMS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . If resistance is 5 ohms or less, go to next step. If resistance is greater than 5 ohms, go to step 4 .
3. Repair short to ground in Orange wire between trunk compartment fuse block and PZM. After repairs, go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.
4. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After repairs, go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.

Controlled power relay supplies power to modules during controlled power usage. Whenever Platform Zone Module (PZM) is awake and ignition switch has been in LOCK position for 15 minutes or less, high power control output is grounded. After 15 minutes, low power control output is turned on. Low power control output will supply up to 2 amps of current for up to 72 hours. If PZM detects more than 2 amps of current is needed, PZM will wake-up and turn on high power control output.

DTC B1973 will set when high power control voltage does not match that of feedback voltage for 2 seconds. When DTC B1973 is set, PZM will turn low power control output off if ignition is in LOCK, OFF or ACC position. DTC B1973 will clear when PZM does not detect malfunction for one monitoring cycle.

1. Perform «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Turn ignition switch to OFF position. Disconnect PZM connectors. Remove controlled power relay located in rear compartment relay center No. 1. Using DVOM, measure voltage between controlled power relay connector terminal B7 (Black wire) and ground. See «WIRING DIAGRAMS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . If battery voltage is indicated, go to step 4 . If battery voltage is not indicated, go to next step.
3. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After repairs, go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.
4. Repair short to battery voltage in Black wire between controlled power relay and PZM. After repairs, go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.

Battery voltage is supplied to Platform Zone Module (PZM) at Brown 24-pin connector C1, terminal B1 (Orange wire). PZM utilizes voltage to perform all PZM functions. PZM constantly measures this battery voltage signal. DTC B1981 will set when PZM receives a value greater than 1500 RPM from PCM, and battery voltage measured at PZM connector C1, terminal B1 (Orange wire) is less than 10 volts for 2 seconds. DTC B1981 will clear when battery voltage is greater than 10 volts in the next monitoring cycle.

1. Perform «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Check for instrument panel DTCs. See appropriate INSTRUMENT PANELS article. If DTC IP1981 does not exist, go to next step. If DTC IP1981 is current, diagnose charging system. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS.
3. Disconnect PZM connectors. Using DVOM, measure voltage between PZM Brown 32-pin connector C2, terminal B1 (Orange wire) and ground. If 10-15 volts is indicated, go to next step. See «WIRING DIAGRAMS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . If other than 10-15 volts is indicated, go to step 5
4. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After repairs, go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.
5. Repair high resistance in Orange wire between PZM and trunk compartment fuse block. After repairs, go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.

DTC B1982: BATTERY VOLTAGE TOO HIGH

Note. DTC B1982 may set if vehicle is connected to a battery charger on fast or boost charge.

Battery voltage is supplied to Platform Zone Module (PZM) at Brown 24-pin connector C1, terminal B1 (Orange wire). PZM utilizes voltage to perform all PZM functions. PZM constantly measures this battery voltage signal. DTC B1982 will set when battery voltage measured is greater than 15.5 volts for 4 monitoring cycles. When DTC B1982 is set, class 2 loss of serial data DTCs will not be set. DTC B1982 will clear when battery voltage is less than 15.5 volts in the next monitoring cycle.

1. Perform «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Turn ignition switch to OFF position. Connect scan tool and select DATA LIST. Select DATA. Observe voltage displayed on scan tool. If reading is 9-15.5 volts or less, go to step 4 . If reading is other than 15.5 volts, go to next step.
3. Use scan tool to view DTCs. If B1982 is current, repair charging system. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. If B1982 is not set, go to next step.
4. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After repairs, go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.

Battery voltage is supplied to Platform Zone Module (PZM) at Brown 24-pin connector C1, terminal B1 (Orange wire). PZM utilizes voltage to perform all PZM functions. PZM constantly measures this battery voltage signal. DTC B1983 will set when battery voltage measured at PZM connector C1, terminal B1 is less than 9 volts for 4 monitoring cycles and DTC B1981 is not set. When DTC B1983 is set, class 2 loss of serial data DTCs will not be set. DTC B1983 will clear when battery voltage is greater than 9.5 volts in the next monitoring cycle.

1. Perform «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Connect scan tool to DLC. Start engine. Use scan tool to view DTCs. If DTC B1983 is current, repair charging system. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS. If DTC B1983 is not current, go to next step.
3. Disconnect PZM connectors. Use DVOM to measure voltage between ground and PZM connector C2 terminal B1 (Orange wire). See «WIRING DIAGRAMS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . If 10-15 volts is indicated, go to next step. If other than 10-15 volts is indicated, go to step 5 .
4. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After repairs, go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.
5. Repair high resistance in Orange wire between PZM and rear compartment fuse block. After repairs, go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.

Daytime Running Lights (DRL) are commanded on and off by Platform Zone Module (PZM) through an output to DRL relay. DRL are activated when ignition switch is in RUN or START position, twilight sentinel is not active, headlights and foglights are off, and transmission is not in Park. When DRL relay is energized, high beams are placed in a series circuit which provides lower illumination for DRL.

A short to ground will be tested when IGN-1 is ON, DRL are inactive, and IPC verifies vehicle is equipped with DRL. A short to battery will be tested when IGN-1 is OFF or both DRL are active, and IPC verifies vehicle is equipped with DRL.

DTC B2470 will set when commanded state of DRL does not match feedback state. When DTC B2470 is set, PZM will continue to command state requested until it is achieved or changes. DTC B2470 will clear when commanded state matches feedback state for 2 consecutive monitoring cycles.

1. Remove DRL relay. Relay is located in the underhood relay center. Turn ignition on. Use DVOM to measure voltage between ground and DRL relay connector terminal A9 (Pink wire). See «WIRING DIAGRAMS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . If battery voltage is indicated, go to next step. If battery voltage is not indicated, go to step 4 .
2. Install DRL relay. Disconnect PZM connector C2. Connect fused jumper between PZM connector C2 terminal D5 (Light Gray/Black wire) and ground. If Daytime Running Lights (DRL) turn on, go to next step. If DRL do not turn on, go to step 5 .
3. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After repairs, recheck DRL operation.
4. Repair open or short to ground in Pink wire between underhood fuse block and underhood relay center. After repairs, recheck DRL operation.
5. Check for open in Light Gray/Black wire between PZM and underhood relay center. If circuit is okay, go to next step. If faulty circuit is found, go to step 7 .
6. Replace DRL relay. After repairs, recheck DRL operation.
7. Repair faulty circuits. After repairs, recheck DRL operation.

Interior lights are commanded by Platform Zone Module (PZM) through an output to courtesy lights relay. When courtesy lights relay is energized, ground is provided for interior lights.

A short to ground will be tested when inadvertent power is active, interior lights output is inactive, and DTC B1971 is not set as current. A short to battery will be tested when inadvertent power is active, interior lights output is active, and DTC B1971 is not set as current.

DTC B2471 will set when commanded state of interior lights does not match feedback state. When DTC B2471 is set, PZM will continue to command state requested until IPC revokes request. DTC B2471 will clear when commanded state matches feedback state.

1. Turn ignition off. Remove courtesy light relay from rear compartment relay center No. 2. Connect scan tool to DLC. Select BCM TEST and inadvertent power. Turn inadvertent power ON. Use DVOM to measure voltage between ground and courtesy light relay connector terminal A9 (Orange wire). See «WIRING DIAGRAMS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . If battery voltage is indicated, go to next step. If battery voltage is not indicated, go to step 6 .
2. Use DVOM to measure voltage between courtesy light relay connector terminals A9 (Orange wire) and B7 (Dark Blue wire). If battery voltage is indicated, go to next step. If battery voltage is not indicated, go to step 4 .
3. Replace courtesy light relay. After repairs, recheck courtesy light operation.
4. Check for open in Dark Blue wire between PZM and courtesy light relay. If faulty circuit is found, go to step 7 . If circuit is okay, go to next step.
5. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After repairs, recheck courtesy light operation.
6. Repair open or short to ground in Orange wire between courtesy light relay and underhood fuse block. After repairs, recheck courtesy light operation.
7. Repair suspect wiring. After repairs, recheck courtesy light operation.

Low beams are commanded by Platform Zone Module (PZM) through an output to headlight relay. When output is grounded, headlight input to IPC is also grounded.

A short to ground will be tested when exterior lights power is active, low beam output is inactive, headlight switch is not active, and DTC B1970 is not set as current. A short to battery will be tested when exterior lights power is active, low beam output is active, and DTC B1970 is not set as current.

DTC B2472 will set when commanded state of low beams does not match feedback state. When DTC B2472 is set, PZM will continue to command state requested until IPC revokes request. DTC B2472 will clear when commanded state matches feedback state.

1. Connect scan tool. Turn ignition switch to ON position. Turn headlight switch off. Using scan tool, select BCM TEST. Select LIGHTS, then select LOW BEAM. Using scan tool, turn low beams on, then off. If headlights do not come on, go to next step. If headlights come on, go to step 3 .
2. Turn headlight switch on. If headlights come on, go to step 4 . If headlights do not come on, go to step 5 .
3. Disconnect White 16-pin connector C201 (body-to-instrument panel wiring harness, located behind left side of instrument panel, below headlight switch). Using scan tool, turn low beams off. If headlights are off, go to step 6 . If headlights are on, go to step 7 .
4. Cycle ignition. If DTC B2472 is current, go to step 10 . If DTC B2472 is now history, go to step 11 .
5. Check for open in Yellow wire between headlight relay and White 16-pin connector C201 (body-to-instrument panel wiring harness, located behind left side of instrument panel, below headlight switch). If faulty circuit is found, go to step 16 . If circuit is okay, go to step 15 .
6. Disconnect headlight switch connectors. Using DVOM, measure resistance between headlight switch Black 12-pin connector C1, terminal "C" (Yellow wire) and ground. See «WIRING DIAGRAMS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . If resistance is 5 ohms or less, go to step 8 . If resistance is greater than 5 ohms, go to step 9 .
7. Check for short to ground in Yellow wire between PZM, headlight relay, headlight switch and IPC. If faulty circuit is found, go to step 12 . If circuit is okay, go to step 16 .
8. Check for short to ground in Yellow wire between PZM, headlight relay, headlight switch and IPC. If faulty circuit is found, go to step 13 . If circuit is okay, go to step 16 .
9. Replace headlight switch. See appropriate STEERING COLUMN SWITCHES article. After repairs, recheck headlight operation.
10. Check for open in Yellow wire between PZM, headlight relay, headlight switch and IPC. If faulty circuit is found, go to step 14 . If circuit is okay, go to step 16 .
11. Repair intermittent short to battery in Yellow wire between PZM, headlight relay, headlight switch and IPC. After repairs, recheck headlight operation.
12. Replace the headlamp relay. After repairs, recheck headlight operation.
13. Replace IPC. See appropriate ANALOG & ELECTRONIC INSTRUMENT PANELS article. After repairs, recheck headlight operation.
14. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After repairs, recheck headlight operation.
15. Check for open in White wire between PZM connector C2 terminal C16 and headlamp relay. If faulty circuit is found, go to step 12 . If circuit is okay, go to next step.
16. Repair suspect wiring. After repairs, recheck headlight operation.

High beams are commanded by Platform Zone Module (PZM) through an output to HI/LO beam relay. When headlight relay is energized, HI/LO beam relay provides power source to low beams or high beams.

DTC B2473 will set when commanded state of high beams does not match feedback state. When DTC B2473 is set, PZM will continue to command state requested until IPC revokes request. DTC B2473 will clear when commanded state matches feedback state.

1. Turn headlight switch on. Remove high/low beam headlamp relay from underhood relay center. Use DVOM to measure voltage between ground and high/low headlamp relay connector terminal C9 (Orange/Black wire). If battery voltage is indicated, go to next step. If battery voltage is not indicated, go to step 6 .
2. Use DVOM to measure voltage between high/low headlamp relay connector terminals C9 (Orange/Black wire) and D7 (Black/White wire). If battery voltage is indicated, go to next step. If battery voltage is not indicated, go to step 4 .
3. Replace high/low headlamp relay. After repairs, recheck headlight operation.
4. Check for open in Black/White wire between PZM and high/low headlamp relay. If faulty circuit is found, go to next step. If circuit is okay, go to step 7 .
5. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After repairs, recheck headlight operation.
6. Repair open or short to ground in Orange wire between high/low headlamp relay and rear compartment fuse block. After repairs, recheck headlight operation.
7. Repair suspect wiring. After repairs, recheck headlight operation.

Parking lights are commanded by Platform Zone Module (PZM) through an output to parking light relay. When output is grounded, parking light input to IPC is also grounded.

A short to ground will be tested when exterior lights power is inactive, parking light output is active, headlight switch is not active, and DTC B1970 is not set as current. A short to battery will be tested when exterior lights power is active, parking light output is active, and DTC B1970 is not set as current.

DTC B2476 will set when commanded state of parking lights does not match feedback state. When DTC B2476 is set, PZM will continue to command state requested until IPC revokes request. DTC B2476 will clear when commanded state matches feedback state.

1. Connect scan tool. Turn ignition switch to ON position. Turn headlight switch off. Using scan tool, select BCM TEST. Select LIGHTS, then select PARK LAMPS. Using scan tool, turn park lamps on, then off. If park lamps do not come on, go to next step. If park lamps come on, go to step 3 .
2. Turn headlight switch on. If park lamps come on, go to step 4 . If park lamps do not come on, go to step 5 .
3. Disconnect 16-pin connector C203 (body-to-instrument panel wiring harness, located behind left side of instrument panel, below headlight switch). Using scan tool, turn park lamps off. If park lamps are off, go to step 6 . If park lamps are on, go to step 7 .
4. Cycle ignition. If DTC B2476 is current, go to step 10 . If DTC B2476 is now history, go to step 11 .
5. Check for open in Gray/Black wire between headlight relay and White 16-pin connector C203 (body-to-instrument panel wiring harness, located behind left side of instrument panel, below headlight switch). If faulty circuit is found, go to step 14 . If circuit is okay, go to step 15 .
6. Disconnect headlight switch connectors. Using DVOM, measure resistance between headlight switch connector C1, terminal "E" (Gray/Black wire) and ground. See «WIRING DIAGRAMS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . If resistance is 5 ohms or less, go to step 8 . If resistance is greater than 5 ohms, go to step 9 .
7. Check for short to ground in Gray/Black wire between PZM, parklamp relay and headlight switch. If faulty circuit is found, go to step 13 . If circuit is okay, go to step 15 .
8. Repair short to ground in Gray/Black between PZM, headlight relay and headlight switch. After repairs, recheck park lamp system operation.
9. Replace headlight switch. See appropriate STEERING COLUMN SWITCHES article. After repairs, recheck park lamp system operation.
10. Check for open in Gray/Black wire between PZM, headlight relay and headlight switch. If faulty circuit is found, go to step 13 . If circuit is okay, go to step 15 .
11. Repair intermittent short to battery in Gray/Black wire between PZM, headlight relay and headlight switch. After repairs, recheck park lamp system operation.
12. Replace the park lamp relay. After repairs, recheck headlight operation.
13. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After repairs, recheck headlight operation.
14. Check for open in White wire between PZM connector C2 terminal C16 and park lamp relay. If faulty circuit is found, go to step 12 . If circuit is okay, go to next step.
15. Repair suspect wiring. After repairs, recheck headlight operation.

When Platform Zone Module (PZM) receives input that transaxle is in reverse, PZM energizes reverse light relay which will turn on back-up lights. When back-up lights have been commanded on, PZM constantly measures voltage at Brown 32-pin connector C2, terminal D14 (Dark Green wire). DTC B2477 will set when voltage is approximately equal to ground. DTC B2477 will clear when voltage is greater than ground for at least one monitoring cycle.

If DTC B2477 is set, check for short to ground in Dark Green wire between PZM Brown 32-pin connector C2, terminal D14 and reverse light relay. See WIRING DIAGRAMS . See COMPONENT LOCATIONS .

When Platform Zone Module (PZM) receives input that transaxle is in Reverse, PZM energizes reverse light relay which will turn on back-up lights. When back-up lights have been commanded on, PZM constantly measures voltage at Brown 32-pin connector C2, terminal D14 (Dark Green wire). DTC B2478 will set when voltage is not at ground potential for at least 2 seconds. DTC B2478 will clear when voltage is greater than ground for at least one monitoring cycle.

If DTC B2478 is set, check for short to battery in Dark Green wire between PZM Brown 32-pin connector C2, terminal D14 and reverse light relay. See WIRING DIAGRAMS . See COMPONENT LOCATIONS .

When transaxle is in Park, Platform Zone Module (PZM) controls park relay output low to enable Brake Transaxle Shift Interlock (BTSI). PZM will continuously monitor this voltage at PZM Brown 32-pin connector C2, terminal C15 (Orange/Black wire).

DTC B2502 will set when park relay output is not active, IGN-1 input exists, and PZM determines output is low for 2 consecutive monitoring cycles. DTC B2502 will clear when park relay output is not active, IGN-1 input exists, and PZM determines output is high for one monitoring cycle.

1. Perform «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Turn ignition switch to OFF position. Disconnect PZM connectors. Remove PARK relay. Using DVOM, measure resistance between PZM connector C2 terminal C15 (Orange/Black wire) and ground. See «WIRING DIAGRAMS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . If reading is 0-5 ohms, go to next step. If reading is not 0-5 ohms, go to step 4 .
3. Repair short to ground in Orange/Black wire between PARK relay and PZM. After repairs, go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.
4. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After repairs, go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.

When transaxle is in Park, Platform Zone Module (PZM) controls park relay output low to enable Brake Transaxle Shift Interlock (BTSI). PZM will continuously monitor this voltage at PZM Brown 32-pin connector C2, terminal C15 (Orange/Black wire).

DTC B2503 will set when park relay output is active and PZM determines output is high for 2 consecutive monitoring cycles. DTC B2503 will clear when park relay output is active and PZM determines output is low for 2 monitoring cycles.

1. Perform «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Turn ignition switch to OFF position. Disconnect PZM connectors. Remove PARK relay. Using DVOM, measure voltage between PZM connector C2 terminal C15 (Orange/Black wire) and ground. See «WIRING DIAGRAMS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . If battery voltage is indicated, go to next step. If battery voltage is not indicated, go to step 4 .
3. Repair short to battery voltage in Orange/Black wire between PARK relay and PZM. After repairs, go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.
4. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After repairs, go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.

When vehicle is not being used for long periods of time, Platform Zone Module (PZM) can be commanded into a storage mode to conserve power. DTC B2550 will set 20 minutes after storage mode has been entered. DTC B2550 will clear when ignition switch is turned from LOCK position.

A test is run to determine if trunk tamper switch is active when Platform Zone Module (PZM) is in a off, idle, ready to arm, arm initiated or arm delay state. DTC B2719 will set when PZM determines trunk tamper switch has been active for 2 seconds. When DTC B2719 is set, UTD will still arm, disregarding input from trunk tamper switch. DTC B2719 will clear when trunk tamper switch is not active on next ignition switch transition to RUN or CRANK position.

1. Perform «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Turn ignition switch to OFF position. Disconnect PZM connectors. Using DVOM, measure resistance between PZM connector C2, terminal A7 (Light Blue wire) and ground. See «WIRING DIAGRAMS»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) . If resistance is 0-5 ohms, go to step 4 . If resistance is other than 0-5 ohms, go to next step.
3. Replace PZM. See «PLATFORM ZONE MODULE (PZM)»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules) under REMOVAL & INSTALLATION. After repairs, go to step 7 .
4. Disconnect trunk tamper switch Black 3-pin connector. Using DVOM, measure resistance between PZM connector C2, terminal A7 (Light Blue wire) and ground. If resistance is 0-5 ohms, go to next step. If resistance is other than 0-5 ohms, go to step 6 .
5. Repair short to ground in Light Blue wire between trunk tamper switch and PZM. After repairs, go to step 7 .
6. Replace trunk tamper switch. After repairs, go to next step.
7. Turn ignition off. Reconnect all disconnected components and connectors. Turn ignition on. Use scan tool to clear DTCs. Go to «BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__body-control-module-diagnostic-system-check) under SYSTEM TESTS.

When ignition switch is in RUN position, control modules that communicate on class 2 data bus transmit a State Of Health (SOH) message every 2 seconds to indicate system is operating properly. DTC U1016 will set when Platform Zone Module (PZM) does not receive SOH message from Powertrain Control Module (PCM) after 3 consecutive monitoring cycles. DTC U1016 will clear when PCM transmits SOH message to PZM.

1. Perform «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Attempt to establish communication with PCM using scan tool. If communication cannot be established, diagnose and repair problem in PCM. See ON-BOARD DIAGNOSTICS (OBD) SYSTEM CHECK in SELF-DIAGNOSTICS - GASOLINE EXCEPT METRO, PRIZM & TRACKER article in ENGINE PERFORMANCE. If communication can be established, go to next step.
3. Check for intermittent open in Purple wire. See appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING DIAGRAMS. After repairs, go to next step.
4. Turn ignition off. Reconnect all disconnected components and connectors. Turn ignition on and use scan tool to clear DTCs. Go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) under SYSTEM TESTS.

When ignition switch is in RUN position, control modules that communicate on class 2 data bus transmit a State Of Health (SOH) message every 2 seconds to indicate system is operating properly. DTC U1088 will set when Platform Zone Module (PZM) does not receive SOH message from Sensing and Diagnostic Module (SDM) after 3 consecutive monitoring cycles. DTC U1088 will clear when SDM transmits SOH message to PZM.

1. Perform «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Attempt to establish communication with SDM using scan tool. If communication cannot be established, diagnose and repair problem in SDM. See AIR BAG SERVICE & REPAIR MANUAL. If communication can be established, go to next step.
3. Check for intermittent open in Purple wire. See appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING DIAGRAMS. After repairs, go to next step.
4. Turn ignition off. Reconnect all disconnected components and connectors. Turn ignition on and use scan tool to clear DTCs. Go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) under SYSTEM TESTS.

When ignition switch is in RUN position, control modules that communicate on class 2 data bus transmit a State Of Health (SOH) message every 2 seconds to indicate system is operating properly. DTC U1096 will set when Platform Zone Module (PZM) does not receive SOH message from Instrument Panel Cluster (IPC) after 3 consecutive monitoring cycles. DTC U1096 will clear when IPC transmits SOH message to PZM.

1. Perform «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Attempt to establish communication with IPC using scan tool. If communication cannot be established, diagnose and repair problem in IPC. See appropriate ANALOG & ELECTRONIC INSTRUMENT PANELS article. If communication can be established, go to next step.
3. Check for intermittent open in Purple wire. See appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING DIAGRAMS. After repairs, go to next step.
4. Turn ignition off. Reconnect all disconnected components and connectors. Turn ignition on and use scan tool to clear DTCs. Go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) under SYSTEM TESTS.

When ignition switch is in RUN position, control modules that communicate on class 2 data bus transmit a State Of Health (SOH) message every 2 seconds to indicate system is operating properly. DTC U1128 will set when Platform Zone Module (PZM) does not receive SOH message from Integrated Radio Controller (IRC) after 3 consecutive monitoring cycles. DTC U1128 will clear when IRC transmits SOH message to PZM.

1. Perform «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Attempt to establish communication with radio using scan tool. If communication cannot be established, diagnose and repair problem in radio. If communication can be established, go to next step.
3. Check for intermittent open in Purple wire. See appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING DIAGRAMS. After repairs, go to next step.
4. Turn ignition off. Reconnect all disconnected components and connectors. Turn ignition on and use scan tool to clear DTCs. Go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) under SYSTEM TESTS.

When ignition switch is in RUN position, control modules that communicate on class 2 data bus transmit a State Of Health (SOH) message every 2 seconds to indicate system is operating properly. DTC U1153 will set when Platform Zone Module (PZM) does not receive SOH message from Climate Control Panel (CCP) after 3 consecutive monitoring cycles. DTC U1153 will clear when CCP transmits SOH message to PZM.

1. Perform «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Attempt to establish communication with Climate Control Panel (CCP) using scan tool. If communication cannot be established, diagnose and repair problem in CCP. See appropriate AUTOMATIC A/C-HEATER SYSTEMS article in AIR CONDITIONING & HEATING. If communication can be established, go to next step.
3. Check for intermittent open in Purple wire. See appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING DIAGRAMS. After repairs, go to next step.
4. Turn ignition off. Reconnect all disconnected components and connectors. Turn ignition on and use scan tool to clear DTCs. Go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) under SYSTEM TESTS.

When vehicle is started, Platform Zone Module (PZM) requests information from other modules on class 2 serial data line. DTC U1255 will set when PZM requests information from a particular module, and that module is not "on-line". PZM will then use default values. DTC U1255 will clear when module providing the requested informations comes back "on-line".

1. Perform «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Attempt to establish communication with all modules using scan tool. If communication cannot be established, diagnose and repair problem in appropriate module. If communication can be established, go to next step.
3. Repair intermittent connections in Purple wire. See appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING DIAGRAMS. After repairs, go to next step.
4. Turn ignition off. Reconnect all disconnected components and connectors. Turn ignition on and use scan tool to clear DTCs. Go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) under SYSTEM TESTS.

When Platform Zone Module (PZM) is energized, it monitors class 2 serial data line for a short to ground. DTC U1300 will set when PZM determines class 2 serial data line is shorted to ground for 10 seconds or more. PZM will then use default values. DTC U1300 will clear when PZM determines class 2 serial data line is no longer shorted to ground.

1. Perform «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Attempt to establish communication with all modules using scan tool. If communication cannot be established, diagnose and repair problem in appropriate module. If communication can be established, go to next step.
3. Repair intermittent connections in Purple wire. See appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING DIAGRAMS. After repairs, go to next step.
4. Turn ignition off. Reconnect all disconnected components and connectors. Turn ignition on and use scan tool to clear DTCs. Go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) under SYSTEM TESTS.

When Platform Zone Module (PZM) is energized, it monitors class 2 serial data line for a short to battery. DTC U1301 will set when PZM determines class 2 serial data line is shorted to battery for 10 seconds or more. PZM will then use default values. DTC U1301 will clear when PZM determines class 2 serial data line is no longer shorted to battery.

1. Perform «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) under SYSTEM TESTS. Go to next step.
2. Attempt to establish communication with all modules using scan tool. If communication cannot be established, diagnose and repair problem in appropriate module. If communication can be established, go to next step.
3. Repair intermittent short to battery voltage in Purple wire. See appropriate wiring diagram in DATA LINK CONNECTORS article in WIRING DIAGRAMS. After repairs, go to next step.
4. Turn ignition off. Reconnect all disconnected components and connectors. Turn ignition on and use scan tool to clear DTCs. Go to «DATA LINK COMMUNICATIONS DIAGNOSTIC SYSTEM CHECK»(/cadillac/deville-concours/i-final-1999-1999/remont/body-cab-control-systems/#body-control-modules__data-link-communications-diagnostic-system-check) under SYSTEM TESTS.

REMOVAL & INSTALLATION

Note. Body Control Module (BCM) may also be referred to as Platform Zone Module (PZM).

1. Disconnect negative battery cable. Remove COMFORT fuse (10-amp) from trunk compartment fuse block. Remove rear seat cushion by pressing down and rearward on front edge of seat to disengage retainers. Open trunk and remove sill plate on rear of trunk area. Remove cargo net and fasteners, spare tire cover and spare tire. Remove CD change if equipped. Remove retainers and trunk trim panel.
2. Remove nuts from top rear of seat back. Remove nuts from bottom center of seat back. Remove rear seat back. Locate electronic module center, attached to back of rear seat. (Scheme 4) Remove nuts from lower section of electronic module center and lay board down in trunk. Locate PZM and disconnect PZM harness connectors. Remove PZM from vehicle.
3. To install, reverse removal procedure. Install COMFORT fuse in trunk compartment fuse block. Reconnect negative battery cable. Recheck operation.

Scheme 4

Body Control Module (BCM) Wiring Diagram (DeVille & Eldorado). Scheme 5

See also:
• PZM DTC DEFINITIONS
• Data Link Communications Diagnostic System Check
• Scan Tool Will Not Communicate With Class 2 Serial Data
• B1982
• COMPONENT LOCATIONS
• DATA LINK COMMUNICATIONS SYSTEM CHECK
• BODY CONTROL MODULE DIAGNOSTIC SYSTEM CHECK