DESCRIPTION & OPERATION
Vehicle has 2 module communications networks. The Powertrain Control Module (PCM), Passive Anti-Theft System (PATS) module and Electronic Automatic Temperature Control (EATC) module are connected to the multiplex communications network through a pair of twisted wires or BUS. The BUS network is also referred to as Standard Corporate Protocol (SCP). The BUS consists of a (+) circuit No. 914 and a (-) circuit No. 915. The Restraint Control Module (RCM), Generic Electronic Module/Central Timer Module (GEM/CTM), Remote Anti-Theft Personality (RAP) module, 4-Wheel Anti-Lock Brake System (4WABS) module, Driver Seat Module (DSM), Parking Aid Module (PAM) and air suspension control module are connected to the International Standards Organization (ISO) 9141 diagnostic communications network through a single wire (circuit No. 70). Both networks are connected to the Data Link Connector (DLC). This article is used to diagnose BUS and ISO communications network circuit faults. For module locations, see COMPONENT LOCATIONS table.
| Component | Location |
|---|---|
| Air Suspension Control Module | Behind Left Center Of Instrument Panel |
| Data Link Connector (DLC) | Below Driver's Side Of Instrument Panel, To Right Of Steering Column |
| Driver's Seat Module (DSM) | Underneath Driver's Seat |
| Electronic Automatic Temperature Control Module (EATC) | Behind Center Of Instrument Panel |
| Generic Electronic Module (GEM)/Central Timer Module (CTM) | Behind Center Of Instrument Panel |
| Parking Aid Module (PAM) | Behind Spare Tire |
| Passive Anti-Theft System (PATS) Control Module | Behind Top Right Side Of Instrument Panel |
| Powertrain Control Module (PCM) | Right Side Of Firewall In Engine Compartment |
| Remote Anti-Theft Personality (RAP) Module | Behind Left Rear Quarter Panel |
| Restraint Control Module (RCM) | Behind Right Kick Panel |
| 4-Wheel Anti-Lock Brake System (4WABS) Module | Left Side Of Engine Compartment |
COMPONENT LOCATIONS
ACCESSING PARAMETER IDENTIFICATION (PID)
Turn ignition off. Connect New Generation Star (NGS) tester to Data Link Connector (DLC). Following manufacturer's instructions enter PID/DATA MONITOR AND RECORD for desired module. Operate appropriate system and ensure PID expected values are obtained. See appropriate table under PARAMETER IDENTIFICATION (PID) DEFINITIONS .
PARAMETER IDENTIFICATION (PID) DEFINITIONS
| PID | Description | Expected Values |
|---|---|---|
| AS_COMP | Air Suspension Compressor Status | ON, OFF |
| AS_GATE | Air Suspension Front Solenoid Gate Valve Status | ON, OFF |
| AS_VENT | Air Suspension Vent Solenoid Valve Status | ON, OFF |
| BOO_ARC | Brake Pedal Position Switch Input | ON, OFF |
| CCNTARC | Number Of Continuous DTCs Counted By Air Suspension Control Module | One Count Per Bit |
| DR_OPEN | Door Ajar Input | CLOSED, CLOSED |
| F_FILL | Air Suspension Front Fill Solenoid Valve Status | ON, OFF |
| HGTSENS | Height Sensor | ON, OFF |
| IGN_RUN | Detection Of Ignition Switch In RUN Position | NotRUN, RUN |
| OFFROAD | Vehicle Off Road Status | ON, OFF |
| PCM_ACC | Acceleration Signal From PCM | YES, NO |
| R_FILL | Rear Fill Solenoid Valve Status | (1) |
| RASGATE | Rear Gate Solenoid Valve Status | (1) |
| RHGTSEN | Value Of Rear Height Sensor | DC Voltage Value |
| STEER_A | Electronic Steering Sensor A Signal | HIGH, LOW |
| STEER_B | Electronic Steering Sensor B Signal | HIGH, LOW |
| VBATARC | Battery Voltage Value To Air Suspension Control Module | DC Voltage Value |
| VSS_ARC | Displays Vehicle Speed Sensor Input To Air Suspension Control Module | VSS Signal In KPH Or MPH |
| (1) Expected value should be OFF- - -, OFFO- -, OFF-B-, OFF- - G, ON- - -, ONO- -, ON-B-, ON- - G | ||
| (1) | Expected value should be OFF- - -, OFFO- -, OFF-B-, OFF- - G, ON- - -, ONO- -, ON-B-, ON- - G |
AIR SUSPENSION CONTROL MODULE PID INDEX
| PID | Description | Expected Value |
|---|---|---|
| R_WP_MD | Rear Wiper Mode Switch Status (GEM Only) | OFF, INTVL 1-2, LOW WASH |
| VSS_GEM | Vehicle Speed Input | 0-255 KPH |
| PARK_SW | External Access Ajar Switch Status | OFF, ON |
| D_DR_SW | Left Front Door Ajar Switch Status | CLOSED, AJAR |
| DR_DSRM | Door Disarm Switch Status | L_DOOR, R_DOOR, LIFT_G, OFF |
| DR_UNLK | All Doors Unlock Ouput State | ON- - -, OFF- - -, ON-B-, OFFO-G |
| P_DR_SW | Right Passenger Door Ajar Switch Status | CLOSED, AJAR |
| IGN_KEY | Key In Ignition Status | IN, OUT |
| IGN_GEM | Ignition Switch Status | START, RUN, OFF, ACC |
| BATSAV | Battery Saver Relay Circuit | ON- - -, OFF- - -, ON-B-, OFFO-G |
| VBATGEM | Battery Voltage | 0.0 VDC - 14.3 VDC |
| LGATESW | Liftgate Ajar Switch Status | CLOSED, AJAR |
| LRDR_SW | Left Rear Door Ajar Switch Status | CLOSED, AJAR |
| RRDR_SW | Right Rear Door Ajar Switch Status | CLOSED, AJAR |
| INTLMP | Illuminated Entry Relay Circuit | ON- - -, OFF- - -, ON-B-, OFFO-G |
| CLTCHSW | Trans Clutch Interlock Switch (GEM Only) | ENGAGED, NOT ENGAGED |
| NTRL_SW | Neutral Safety Switch Input | NTRL, notNTRL |
| MTR_CCW | Trans Transfer CCW Motor Output | ON- - -, OFF- - -, ON-B-, OFFO-G |
| MTR_CW | CW Shift Relay Coil Status | ON- - -, OFF- - -, ON-B-, OFFO-G |
| 4WD_SW | 4WD Switch Status (GEM Only) | AUTO, 4WDLOW, 4WDHIGH |
| 4WDELCL | 4WD Electronic Clutch | ON- - -, OFF- - -, ON-B-, OFFO-G |
| TRANSGR | Transmission Gear Status | REV, notREV |
| 4WDCLCH | 4WD Electronic Clutch Output Status (GEM Only) | ON- - -, OFF- - -, ON-B-, OFFO-G |
| 4WDLOW | 4WD Low Indicator Status (GEM Only) | ON- - -, OFF- - -, ON-B-, OFFO-G |
| 4WDHIGH | 4WD High Indicator Status (GEM Only) | ON- - -, OFF- - -, ON-B-, OFFO-G |
| PLATE_A | Transfer Case Contact Plate Switch A (GEM Only) | OPEN, CLOSED |
| PLATE_B | Transfer Case Contact Plate Switch B (GEM Only) | OPEN, CLOSED |
| PLATE_C | Transfer Case Contact Plate Switch C (GEM Only) | OPEN, CLOSED |
| PLATE_D | Transfer Case Contact Plate Switch D (GEM Only) | OPEN, CLOSED |
| BOO_GEM | Brake Pedal Position Switch Input (GEM Only) | ON, OFF |
| HALLPWR | Hall Effect Speed Sensor Power (GEM Only) | ON, OFF, ON-B-, OFFO-G |
| 4WDCLST | FWD Clutch PWM Output Status (GEM Only) | ON, OFF, ON-B-, OFFO-G |
| TRA_RSP | Rear Shaft Speed (GEM Only) | 0-255 MPH |
| TRA_FSP | Front Shaft Speed (GEM Only) | 0-255 MPH |
| PLATEPW | Transfer Case Contact Plate Ground Output (GEM Only) | ON, OFF, ON-B-, OFFO-G |
| PWR_RLY | ABS Active Input | ON, OFF |
| NTF | Neutral Tow Function (GEM Only) | ON, OFF |
| NTF_LMP | Neutral Tow Light (GEM Only) | ON, OFF |
| D_SBLT | Driver's Seat Belt Status | IN, OUT |
| IPCHIME | External Chime Request | ON, OFF |
| SBLTMP | Seat Belt Indicator Status | ON, OFF, ON-B-, OFFO-G |
| DRAJR_L | Door Ajar Warning Light Circuit | ON, OFF |
| D_PWRLY | On Touch Down Relay Coil Circuit Status (GEM Only) | ON- - -, OFF- - -, ON-B-, OFFO-G |
| D_PWAMP | Driver's Power Window Motor Current (GEM Only) | .25 Amp Increments |
| D_PWPK | Driver's Power Window Motor Peak Current (GEM Only) | .25 Amp Increments |
| ACCDLY | Accessory Delay Relay Coil Circuit (GEM Only) | ON- - -, OFF- - -, ON-B-, OFFO-G |
| RDEF_SW | Rear Defrost Control Switch Status | ON- - -, OFF- - -, ON-B-, OFFO-G |
| RDEFRLY | Rear Window Defrost Relay Coil Circuit | ON- - -, OFF- - -, ON-B-, OFFO-G |
| WASHRLY | Washer Relay Status | ON- - -, OFF- - -, ON-B-, OFFO-G |
| WPPK_PK | Wiper Park-To-Park Time | 0-6.5 Seconds |
| WPMODE | Wiper Control Mode Status | WASH, OPEN INVLD, OFF, INTVL 1-7, LOW, HIGH |
| WPPRKSW | Wiper Motor Status | PARKED, notPRK |
| WPRUN | Wiper Mode Run Relay | ON- - -, OFF- - -, ON-B-, OFFO-G |
| WPHISP | Wiper HI/LO Relay Status | ON- - -, OFF- - -, ON-B-, OFFO-G |
| WASH_SW | Washer Pump Relay Switch Status | ON, OFF, ON-B-, OFFO-G |
| R_WP_UP | Rear Wiper Up Relay Staus (GEM Only) | ON, OFF, ON-B-, OFFO-G |
| R_WP_DN | Rear Wiper Down Relay Staus (GEM Only) | ON, OFF, ON-B-, OFFO-G |
| R_WP_SW | Rear Wiper Input Switch Staus (GEM Only) | WPLOW, OFF, WPHIGH |
| R_WP_PK | Rear Wiper Park Staus (GEM Only) | PARKED, notPRK |
| (1) Vehicles equipped with 4WD and/or power windows are equipped with a GEM. All other vehicle are equipped with a CTM. | ||
| (1) | Vehicles equipped with 4WD and/or power windows are equipped with a GEM. All other vehicle are equipped with a CTM. |
GENERIC ELECTRONIC MODULE/CENTRAL TIMER MODULE (GEM/CTM) PID INDEX (1)
| PID | Description | Expected Value |
|---|---|---|
| CCNTPATS | Number Of Continuous DTCs | On count Per Bit |
| IGN_PAT | Ignition Switch Position | RUN/ACC, OFF |
| NUMKEYS | Number Of Ignition Keys Programmed | 0-8 |
| M_KEYS | Programmed Key In Ignition | YES, ON |
| ENABL_S | Has PATS Enable Vehicle | ENABLE, DISABLED |
| ACCESS | Security Access Status | TIMED, CODED |
| MIN#KEYS | Minimum Number Of Keys Required To Start Vehicle | 2-8 |
| ANTISCN | Time Out For Unprogrammed PATS Key | ACTIVE, notACT |
| PCM_ID | Is PCM ID Stored In PATS | STORED, notSTR |
| SPAREKY | Can You Add Spare Key With 2 Programmed Keys | YES, NO |
| PCM_VFY | PCM ID matches Between PCM & PATS | YES, NO |
PASSIVE ANTI-THEFT SYSTEM (PATS) MODULE PID INDEX
| PID | Description | Expected Values |
|---|---|---|
| AL_EVT# | Last Eight Alarm Events | NO_EVT, DROPEN, HOODTR, IGNTAM, PANIC |
| BOO_RAP | Brake Switch Input | OFF, ON |
| HOOD_SW | Hood Switch Input | NotPUN, PUNCHED |
| IGN_RES | Ignition Lock Anti-Theft Switch | HIGH |
| KEYCODE | Factory 5 Digit Unlock Code For Keypad | 5 Digit#, INVLD |
| KEY_PAD | Keypad Switch Input | 1/2, 3/4, 5/6, 7/8, 9/0 |
| DOORRAP | Door Ajar Status Input From GEM | CLOSED, AJAR |
| DR_DARM | Door Disarm Input | NotACTIVE, ACTIVE |
| IGN_RAP | Ignition Switch | RUN, OFF |
| DD_LOCK | Power Door Lock/Unlock Status | LOCK, UNLOCK, OFF, SHORT |
| NOTHEFT | Theft Only State | NO, YES |
| NOREMOT | Remote Only Input State | NO, YES |
| TRANSGR | Transmission Gear | NotREV, REV |
REMOTE ANTI-THEFT PERSONALITY (RAP) MODULE PID INDEX
| PID | Description | Expected Value |
|---|---|---|
| CCNT | Number Of Continuous DTCs In RCM | DTCS |
| DABAGR | Driver Air Bag Circuit Resistance | 1.8-4.1 Ohms |
| PABAGR | Passenger Air Bag Circuit Resistance | 1.4-3.6 Ohms |
| DABAG2 | Driver Side Impact Air Bag Circuit Resistance | 1.4-3.6 Ohms |
| PABAG2 | Passenger Side Impact Air Bag Circuit Resistance | 1.4-3.6 Ohms |
| BRACKET | Bracket Ground Resistance | Less Than 100 Ohms |
| VID#1 | Program Vehicle ID Pin 10 | No Connection |
| VID#2 | Program Vehicle ID Pin 13 | Ignition |
| VID#3 | Program Vehicle ID Pin 14 | No Connection |
RESTRAINT CONTROL MODULE (RCM) PID INDEX
| PID | Description | Expected Value |
|---|---|---|
| ABSLF_I | Left Front ABS Inlet Valve | ON, OFF |
| ABSLF_O | Left Front ABS Outlet Valve | ON, OFF |
| ABSRF_I | Right Front ABS Inlet Valve | ON, OFF |
| ABSRF_O | Right Front ABS Outlet Valve | ON, OFF |
| ABSR_I | Rear ABS Inlet Valve | ON, OFF |
| ABSR_O | Rear ABS Outlet Valve | ON, OFF |
| BOO_ABS | Brake Switch Input | ON/OFF |
| CONTABS | Number Of Continuous DTCs | One Bit Per Count |
| LF_WSPD | Left Front Wheel Speed Signal | 0-255 KPH |
| R_WSPD | Rear Wheel Speed Signal | 0-255 KPH |
| RF_WSPD | Right Front Wheel Speed Signal | 0-255 KPH |
| ACCLSW1 | Acceleration Switch Position 1 Input | ACT, notACT |
| ACCLSW2 | Acceleration Switch Position 2 Input | ACT, notACT |
| 4WDLOW | 4WD Low Input | ON, OFF |
4-WHEEL ANTI-LOCK BRAKE SYSTEM (4WABS) MODULE PID INDEX