ABS DODGE RAM 1999 Service Repair Manual

Intake Air Temperature (IAT) Sensor
See appropriate DTC P0112: IAT SENSOR VOLTAGE LOW and DTC
P0113: IAT SENSOR VOLTAGE HIGH tests in SELF-DIAGNOSTICS - JEEP,
TRUCKS & RWD VANS article.
Manifold Absolute Pressure (MAP) Sensor
See appropriate DTC P0107: MAP SENSOR VOLTAGE TOO LOW and DTC
P0108: MAP SENSOR VOLTAGE TOO HIGH tests in SELF-DIAGNOSTICS - JEEP,
TRUCKS & RWD VANS article.
Transmission Temperature (TRANS Temp) Sensor
See appropriate DTC P0711: TRANSMISSION TEMPERATURE SENSOR,
NO TEMPERATURE RISE AFTER START, DTC P0712: TRANSMISSION TEMPERATURE
SENSOR VOLTAGE TOO LOW, and DTC P0713: TRANSMISSION TEMPERATURE SENSOR
VOLTAGE TOO HIGH tests in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS
article.
Throttle Position (TP) Sensor
See appropriate DTC P0122: THROTTLE POSITION SENSOR VOLTAGE
LOW and DTC P0123: THROTTLE POSITION SENSOR VOLTAGE HIGH tests in
SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
Vehicle Speed Sensor (VSS)
See appropriate DTC P0500: NO VEHICLE SPEED SENSOR SIGNAL
test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
SOLENOIDS
Evaporative (EVAP) Purge Solenoid
See appropriate DTC P0443: EVAP PURGE SOLENOID CIRCUIT test
in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
Leak Detection Pump (LDP) Solenoid
See appropriate DTC P1495: LEAK DETECTION PUMP SOLENOID
CIRCUIT test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
Speed Control (S/C) Solenoid
See appropriate DTC P1595: SPEED CONTROL SOLENOID CIRCUITS
test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
Transmission Governor Pressure Solenoid
See appropriate DTC P0748: GOVERNOR PRESSURE
SOLENOID/TRANSMISSION RELAY CIRCUITS test in SELF-DIAGNOSTICS - JEEP,
TRUCKS & RWD VANS article.
Transmission 3-4 Solenoid
See appropriate DTC P0783: TRANSMISSION 3-4 SHIFT SOLENOID,
NO RPM DROP AT 3-4 SHIFT test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD
VANS article.
SWITCHES
Leak Detection Pump (LDP) Switch
See appropriate DTC P1494: LEAK DETECTION PUMP SWITCH OR
MECHANICAL FAULT test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS
article.
Park/Neutral (P/N) Switch
See appropriate DTC P1899: PARK/NEUTRAL SWITCH STUCK IN PARK
OR IN GEAR test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
Power Steering (PS) Switch
See appropriate DTC P0551: POWER STEERING SWITCH FAILURE test

Check the following:
* Check secondary ignition system
* Check engine vacuum
* Check fuel pressure
* Check Engine Coolant Temperature (ECT) sensor calibration
* Check Throttle Position (TP) sensor calibration
* Check Manifold Absolute Pressure (MAP) calibration
* Check minimum idle airflow
* Check Idle Air Control (IAC) motor operation
* Check engine mechanical condition
* Check evaporative system
* Check EGR system
* Check coolant temperature sensor and connector
* Check Intake Air Temperature (IAT) sensor calibration
STARTS BUT STALLS
Check the following:
* Check secondary ignition system
* Check PCM power and ground circuits
* Check fuel pressure
* Check Engine Coolant Temperature (ECT) sensor calibration
* Check Throttle Position (TP) sensor calibration
* Check Manifold Absolute Pressure (MAP) calibration
* Check minimum idle airflow
* Check Idle Air Control (IAC) motor operation
HESITATION OR STUMBLE
Check the following:
* Check secondary ignition system
* Check PCM power and ground circuits
* Check engine vacuum
* Check fuel pressure
* Check Engine Coolant Temperature (ECT) sensor calibration
* Check Throttle Position (TP) sensor calibration
* Check Manifold Absolute Pressure (MAP) calibration
* Check minimum idle airflow
* Check oxygen sensor switching
* Check oxygen sensor heater
* Check Idle Air Control (IAC) motor operation
* Check engine mechanical condition
* Check evaporative system
* Check EGR system
* Check Intake Air Temperature (IAT) sensor calibration
* Check Park/Neutral Position (PNP) switch.
SURGING
Check the following:
* Check secondary ignition system
* Check PCM power and ground circuits
* Check engine vacuum
* Check fuel pressure
* Check Engine Coolant Temperature (ECT) sensor calibration
* Check Throttle Position (TP) sensor calibration
* Check Manifold Absolute Pressure (MAP) calibration
* Check minimum idle airflow

* Check oxygen sensor switching
* Check Idle Air Control (IAC) motor operation
* Check evaporative system.
LACK OF POWER
Check the following:
* Check secondary ignition system
* Check PCM power and ground circuits
* Check fuel pressure
* Check Engine Coolant Temperature (ECT) sensor calibration
* Check Throttle Position (TP) sensor calibration
* Check Manifold Absolute Pressure (MAP) calibration
* Check minimum idle airflow
* Check oxygen sensor switching
* Check Idle Air Control (IAC) motor operation
* Check EGR system.
KNOCKING
Check the following:
* Check secondary ignition system
* Check PCM power and ground circuits
* Check fuel pressure
* Check Engine Coolant Temperature (ECT) sensor calibration
* Check Throttle Position (TP) sensor calibration
* Check Manifold Absolute Pressure (MAP) calibration
* Check minimum idle airflow
* Check oxygen sensor switching
* Check Idle Air Control (IAC) motor operation
* Check evaporative system.
ENGINE MISFIRE
Check the following:
* Check secondary ignition system
* Check PCM power and ground circuits
* Check fuel pressure
* Check minimum idle airflow
* Check oxygen sensor switching
* Check Idle Air Control (IAC) motor operation
* Check EGR system.
BACKFIRE
Check the following:
* Check secondary ignition system
* Check PCM power and ground circuits
* Check fuel pressure
* Check Manifold Absolute Pressure (MAP) calibration
* Check minimum idle airflow
* Check oxygen sensor switching
* Check EGR system.
ROUGH OR ERRATIC IDLE
Check the following:

* Check secondary ignition system
* Check PCM power and ground circuits
* Check engine vacuum
* Check fuel pressure
* Check Engine Coolant Temperature (ECT) sensor calibration
* Check Throttle Position (TP) sensor calibration
* Check Manifold Absolute Pressure (MAP) calibration
* Check minimum idle airflow
* Check oxygen sensor switching
* Check oxygen sensor heater
* Check Idle Air Control (IAC) motor operation
* Check engine mechanical condition
* Check evaporative system
* Check EGR system
* Check Intake Air Temperature (IAT) motor operation
* Check Park/Neutral Position (PNP) switch.
POOR FUEL ECONOMY
Check the following:
* Check secondary ignition system
* Check PCM power and ground circuits
* Check engine vacuum
* Check fuel pressure
* Check Engine Coolant Temperature (ECT) sensor calibration
* Check Throttle Position (TP) sensor calibration
* Check Manifold Absolute Pressure (MAP) calibration
* Check minimum idle airflow
* Check oxygen sensor switching
* Check oxygen sensor heater
* Check Idle Air Control (IAC) motor operation
* Check engine mechanical condition
* Check evaporative system
* Check EGR system
* Check Intake Air Temperature (IAT) motor operation
* Check Park/Neutral Position (PNP) switch.
INTERMITTENTS
INTERMITTENT PROBLEM DIAGNOSIS
Intermittent fault testing requires duplicating circuit or
component failure to identify the problem. These procedures may lead
to PCM setting a Diagnostic Trouble Code (FTC) which may help in
diagnosis.
If problem vehicle does not produce FTC, monitor voltage or
resistance values using a DVOM while attempting to reproduce
conditions causing intermittent fault. A status change on DVOM
indicates a fault has been located.
Use a DVOM to pinpoint faults. When monitoring voltage,
ensure ignition switch is in ON position or engine is running. Ensure
ignition switch is in OFF position or negative battery cable is
disconnected when monitoring circuit resistance. Status changes on
DVOM during test procedures indicate area of fault.
TEST PROCEDURES
Intermittent Simulation
To reproduce the conditions creating an intermittent fault,
use the following methods:

brakelines are attached to and is mounted in the engine compartment.
ECM OUTPUT SIGNALS
APPS & CKP Output To PCM
See ACCELERATOR PEDAL POSITION SENSOR (APPS) OUTPUT FROM ECM
under PCM INPUT SIGNALS.
CCD Bus
These circuits are connected between Engine Control Module
(ECM) and Powertrain Control Module (PCM) to allow communication
between modules.
DLC Output
Data Link Connector (DLC) is connected to Engine Control
Module (ECM). Using a scan tool, data can be retrieved (output) from\
ECM.
5-Volt Sensor Supply Output
Engine Control Module (ECM) supplies a 5-volt reference
signal to the following sensors:
* Crankshaft Position (CKP) Sensor
* Camshaft Position (CMP) Sensor
* Intake Air Temperature (IAT) Sensor
* Engine Oil Pressure Sensor
* Manifold Absolute Pressure (MAP) Sensor
Engine Control Module (ECM) also supplies voltage to the
following sensors:
* Accelerator Pedal Position Sensor (APPS)
* Intake Air Temperature (IAT) Sensor
* Engine Oil Pressure Sensor
* Engine Coolant Temperature (ECT) Sensor
* Manifold Absolute Pressure (MAP) Sensor
* Water-In-Fuel (WIF) Sensor
Fuel Injection Pump Relay
The Engine Control Module (ECM) energizes the fuel injection
pump and integral Fuel Pump Control Module (FPCM) through the relay.
When ignition is turned on, ECM supplies 12 volts to fuel injection
pump relay, located in Power Distribution Center.
Fuel Pump Control Module (FPCM)
Fuel Pump Control Module (FPCM) controls fuel pump using
inputs from Engine Control Module (ECM). FPCM is integral to top of
fuel pump. ECM and FPCM are interconnected together for fuel injection
control.
Fuel Transfer Pump
Engine Control Module (ECM) supplies power to fuel transfer
pump. Transfer fuel pump supplies fuel under low pressure (14 psi)
while engine is running to fuel injection pump. Fuel transfer pump
supplies an excess of fuel to cool fuel injection pump. Excess fuel is
returned to fuel tank by fuel injection pump.
Intake Manifold Air Heater Relays
Intake manifold air heater relays provide voltage to intake
manifold air heater for warming of intake. See Fig. 5. Warming of
intake air aids in engine starting and improved driveability during
cold ambient temperatures. Intake manifold air heater relays are
mounted on inner wheelwell, below driver's side battery. See Fig. 6.


E - T H EO RY/O PER ATIO N - R W D - G ASO LIN E

1999 D odge P ic ku p R 1500
1999 ENGINE PERFORMANCE
CHRY - Theory & Operation - Trucks & RWD Vans - Gasoline
Dakota, Durango, Ram Pickup, Ram Van, Ram Wagon
INTRODUCTION
This article covers the basic description and operation of
engine performance related systems and components. Read this article
before working on unfamiliar systems.
COMPUTERIZED ENGINE CONTROLS
POWERTRAIN CONTROL MODULE (PCM)
The PCM is a digital computer that controls ignition timing,
air/fuel ratio, fuel injector pulse width, ignition coil(s), spark
advance, emission control devices, cooling fan, charging system, idle
speed, cruise control (if equipped), fuel pump and tachometer. For PCM\
location, see PCM LOCATION. PCM uses data from various input sources
to control output devices in order to achieve optimum engine
performance for all operating conditions.
PCM has voltage converters that convert battery voltage to
regulated 5-volt output. The 5-volt output powers battery temperature
sensor, Camshaft Position (CMP) sensor on models equipped with
Distributorless Ignition System (DIS) or distributor on models without\
DIS, Crankshaft Position (CKP) sensor, Engine Coolant Temperature
(ECT) sensor, Intake Air Temperature (IAT) sensor, logic circuits,
Manifold Absolute Pressure (MAP) sensor, Throttle Position (TP) sens\
or
and Vehicle Speed Sensor (VSS) on some models.
PCM LOCATION









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Application Location
Dakota & Durango ................. Right Front Fender, Near Firewall
Ram Pickup, Ram Van & Ram Wagon .... On Firewall, Near Wiper Motor









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NOTE: Components are grouped into 2 categories. The first category,
INPUT DEVICES, includes components that control or produce
voltage signals monitored by the PCM. The second category,
OUTPUT SIGNALS, includes components controlled by the PCM
(this is accomplished by the PCM grounding individual
circuits).
INPUT DEVICES
Vehicles are equipped with different combinations of input
devices. Not all devices are used on all models. To determine
component location and input usage on a specific model, see
appropriate wiring diagram in WIRING DIAGRAMS article. Available input
signals include:
A/C Switch
Switch signals PCM that A/C has been selected. PCM then
activates A/C compressor clutch relay and maintains idle speed at a
preprogrammed RPM. This is done through control of Idle Air Control

drive plate. PCM uses this information to determine fuel injection
sequence, ignition signal and spark timing.
Cruise Control Switch
Cruise control switch provides PCM with 3 separate inputs.
ON/OFF switch input informs PCM that cruise control system has been
activated. SET/COAST switch input informs PCM that set vehicle speed
has been selected, or if depressed will decelerate until switch is
released. RESUME/ACCEL switch input informs PCM that a previously set
speed has been selected or, if depressed, will increase speed until
released. PCM uses these inputs to control cruise control servo.
Engine Coolant Temperature (ECT) Sensor
ECT sensor monitors engine coolant temperature. PCM uses ECT
sensor information to adjust air/fuel mixture and idle speed and to
control radiator cooling fans as necessary.
Fuel Level Sensor
PCM supplies a 5-volt reference signal to fuel module in gas
tank. Fuel level sensor sends a signal to PCM indicating fuel level.
PCM monitors this signal to prevent a false misfire signal if fuel
level is less than 15 percent. PCM also sends this signal to fuel
gauge.
Heated Oxygen Sensor (HO2S)
HO2S produces a small electrical voltage (0-1 volt) when
exposed to heated exhaust gas. HO2S is electrically heated for faster
warm-up. Heating element is powered through Auto Shutdown (ASD) relay.\
HO2S acts like a rich/lean (air/fuel ratio) switch by
monitoring oxygen content in exhaust gas. This information is used by
PCM to adjust air/fuel ratio by adjusting injector pulse width.
HO2S produces low voltage when oxygen content in exhaust gas
is high. When oxygen content in exhaust gas is low, HO2S produces a
higher voltage.
Ignition Switch
Ignition switch sends signal to PCM indicating whether switch
is on, off or cranking (ST). When PCM receives ON signal, it energizes\
ASD relay coil and supplies power to sensors and actuators. When PCM
receives ST signal, it controls fuel injection rate, idle speed,
ignition timing, etc. for optimum cranking conditions.
Intake Air Temperature (IAT) Sensor
IAT sensor measures temperature of incoming intake air. This
information is used by PCM to adjust air/fuel mixture.
Manifold Absolute Pressure (MAP) Sensor
MAP sensor monitors intake manifold vacuum. Sensor transmits
information on manifold vacuum and barometric pressure to PCM. MAP
sensor information is used with information from other sensors to
adjust air/fuel mixture.
Oil Pressure Sensor
Sensor sends a signal to PCM to indicate oil pressure.
Park/Neutral (P/N) Switch (A/T Models)
This switch may also be referred to as a Park/Neutral
Position (PNP) switch. P/N switch is available on vehicles equipped
with A/T only. Switch prevents engine starter from engaging if vehicle
is in any gear except Park or Neutral.
P/N switch input (varied with gear selection) is used to
determine idle speed, fuel injector pulse and ignition timing.

operating. When ground is supplied to injector by PCM, armature and
pintle inside injector move a short distance against spring and open a
small orifice. Since fuel is under high pressure, a fine spray is
developed.
Modes Of Operation
As input signals to PCM change, PCM adjusts its response to
output devices. Modes of operation come in 2 types, open loop and
closed loop. In open loop mode, PCM is not using input from HO2S and
is responding to preset programming to determine injector pulse width
and ignition timing. In closed loop mode, PCM adjusts ignition timing
and uses input from HO2S to fine tune injector pulse width.
The following inputs may be used to determine PCM mode:
* A/C Control Positions
* A/C Switch
* Battery Voltage
* Brake Switch
* Camshaft Position (CMP) Sensor
* Crankshaft Position (CKP) Sensor
* Engine Coolant Temperature (ECT) Sensor
* Engine Speed (RPM)
* Heated Oxygen Sensor (HO2S)
* Intake Air Temperature (IAT) Sensor
* Manifold Absolute Pressure (MAP) Sensor
* Park/Neutral (P/N) Switch
* Starter Relay
* Throttle Position (TP) Sensor
* Vehicle Speed Sensor (VSS)
From these inputs, PCM determines which mode vehicle is in
and responds appropriately. Not all inputs are used in all modes or by
all models. Modes of operation are:
* Ignition Switch On (Engine Not Running) - This is an open
loop mode. PCM pre-positions IAC motor based on ECT sensor
input. PCM determines atmospheric pressure from MAP sensor
and determines basic fuel strategy. PCM modifies fuel
strategy according to IAT sensor, ECT sensor and TP sensor
inputs. PCM activates ASD relay, which in turn activates fuel
pump for only 2 seconds unless engine is cranked. PCM also
energizes HO2S heater element for approximately 2 seconds
unless engine is cranked.
* Engine Start-Up - This is an open loop mode. When starter is
engaged, PCM receives input from battery voltage, ignition
switch, CKP sensor, CMP sensor, ECT sensor, IAT sensor, MAP
sensor and TP sensor. Based on these inputs, voltage is
applied to fuel injectors with PCM controlling injection
sequence, rate, and pulse width. PCM provides ground for
injectors to fire in proper order.
PCM determines proper ignition timing according to input
received from CKP sensor. If PCM does not receive CKP sensor signal
within 3 seconds after engine begins cranking, fuel injection system
is shut down and a Diagnostic Trouble Code (FTC) is set in PCM memory.\
* Engine Warm-Up - This is an open loop mode. PCM determines
injector pulse width using input information from battery
voltage, CKP sensor, CMP sensor, ECT sensor, IAT sensor, MAP
sensor and TP sensor. PCM also monitors A/C request and P/N
switch (A/T only) for fuel calculation. PCM controls engine
idle speed through IAC motor. PCM controls ignition timing
based on CKP sensor input.

resistance between ground and instrument cluster connector C1 terminal
No. 10 (Violet/Brown wire). If resistance is less than 5 ohms, replace\
instrument cluster. If resistance is 5 ohms or more, repair open
Violet/Brown wire.
BUS (+) & BUS (-) SHORTED TOGETHER
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1 after each repair.
CAUTION: Always turn ignition off prior to disconnecting any module
connector.
1) Turn ignition off. Disconnect Powertrain Control Module
(PCM). PCM is mounted in right side of firewall. Turn ignition on. If
scan tool does not display BUS (+) & BUS (-) SHORTED TOGETHER, repla\
ce
PCM. If scan tool displays BUS (+) & BUS (-) SHORTED TOGETHER, go to\
next step.
2) Turn ignition off. Disconnect anti-lock brake controller
module. Controller is mounted to top of ABS hydraulic unit. Turn
ignition on. If scan tool does not display BUS (+) & BUS (-) SHORTED\
TOGETHER, replace anti-lock brake controller module. If scan tool
displays BUS (+) & BUS (-) SHORTED TOGETHER, go to next step.
3) Turn ignition off. Disconnect instrument cluster. Turn
ignition on. If scan tool does not display BUS (+) & BUS (-) SHORTED\
TOGETHER, replace instrument cluster circuit board. If scan tool
displays BUS (+) & BUS (-) SHORTED TOGETHER, go to next step.
4) Turn ignition off. Disconnect compass mini-trip computer.
Turn ignition on. If scan tool does not display BUS (+) & BUS (-)
SHORTED TOGETHER, replace compass mini-trip computer. If scan tool
displays BUS (+) & BUS (-) SHORTED TOGETHER, go to next step.
5) Turn ignition off. Disconnect radio connector. Turn
ignition on. If scan tool does not display BUS (+) & BUS (-) SHORTED\
TOGETHER, replace radio. If scan tool displays BUS (+) & BUS (-)
SHORTED TOGETHER, go to next step.
6) Turn ignition off and wait 2 minutes. Disconnect Air Bag
Control Module (ACM). ACM is located under center of instrument panel.\
Turn ignition on. If scan tool does not display BUS (+) & BUS (-)
SHORTED TOGETHER, replace ACM. If scan tool displays BUS (+) & BUS (-\
)
SHORTED TOGETHER, go to next step.
7) Turn ignition off. Disconnect Central Timer Module (CTM).\
CTM is located under left side of instrument panel. Turn ignition on.
If scan tool does not display BUS (+) & BUS (-) SHORTED TOGETHER,
replace CTM. If scan tool displays BUS (+) & BUS (-) SHORTED TOGETHE\
R,
go to next step.
8) Disconnect scan tool from DLC. Using external ohmmeter,
measure resistance between terminals No. 3 (Violet/Brown wire) and No.\
11 (White/Black wire) on DLC connector. If resistance is less than 5
ohms, repair short between Violet/Brown wire and White/Dark Green
wire. If resistance is 5 ohms or more, replace scan tool cable or scan
tool as necessary.
BUS BIAS LEVEL TOO LOW (BUS BIAS LEVEL TOO HIGH)
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1 after each repair.
CAUTION: Always turn ignition off prior to disconnecting any module
connector.
1) Disconnect scan tool. Using an external voltmeter, measure

(White/Black wire). Perform CCD BUS test. If scan tool does not
display BUS SHORT TO GROUND, repair open White/Black wire. If scan
tool displays BUS SHORT TO GROUND, replace PCM.
NOT RECEIVING BUS MESSAGES CORRECTLY
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1 after each repair.
CAUTION: Always turn ignition off prior to disconnecting any module
connector.
1) Disconnect anti-lock brake controller module. Controller
module is mounted to top of ABS hydraulic unit. Turn ignition on. If
scan tool displays BUS OPERATIONAL, replace anti-lock brake controller
module. If scan tool does not display BUS OPERATIONAL, go to next
step.
2) Turn ignition off and wait 2 minutes. Disconnect Air Bag
Control Module (ACM). ACM is located under center of instrument panel.\
Turn ignition on. If scan tool displays BUS OPERATIONAL, replace ACM.
If scan tool does not display BUS OPERATIONAL, go to next step.
3) Disconnect Central Timer Module (CTM). CTM is located
under left side of instrument panel. Turn ignition on. If scan tool
displays BUS OPERATIONAL, replace CTM. If scan tool does not display
BUS OPERATIONAL, replace scan tool cable or scan tool.
BUS SHORT TO 5 VOLTS
NOTE: For connector terminal identification and wiring diagrams,
see BODY CONTROL COMPUTER - INTRODUCTION article. Perform
VERIFICATION TEST VER-1 after each repair.
CAUTION: Always turn ignition off prior to disconnecting any module
connector.
1) Turn ignition off. Disconnect Powertrain Control Module
(PCM). PCM is mounted in right side of firewall. Turn ignition on. If
scan tool does not display BUS SHORT TO 5 VOLTS, go to step 10). If
scan tool displays BUS SHORT TO 5 VOLTS, go to next step.
2) Turn ignition off. Disconnect anti-lock brake controller
module. Controller module is mounted to top of ABS hydraulic unit.
Turn ignition on. If scan tool does not display BUS SHORT TO 5 VOLTS,
replace anti-lock brake controller module. If scan tool displays BUS
SHORT TO 5 VOLTS, go to next step.
3) Turn ignition off. Disconnect instrument cluster. Turn
ignition on. If scan tool does not display BUS SHORT TO 5 VOLTS,
replace instrument cluster circuit board. If scan tool displays BUS
SHORT TO 5 VOLTS, go to next step.
4) Turn ignition off. Disconnect compass mini-trip computer.
Turn ignition on. If scan tool does not display BUS SHORT TO 5 VOLTS,
replace compass mini-trip computer. If scan tool displays BUS SHORT TO
5 VOLTS, go to next step.
5) Turn ignition off. Disconnect CCD radio. Turn ignition on.
If scan tool does not display BUS SHORT TO 5 VOLTS, replace radio. If
scan tool displays BUS SHORT TO 5 VOLTS, go to next step.
6) Turn ignition off and wait 2 minutes. Disconnect Air Bag
Control Module (ACM). ACM is located under center of instrument panel.\
Turn ignition on. If scan tool does not display BUS SHORT TO 5 VOLTS,
replace ACM. If scan tool displays BUS SHORT TO 5 VOLTS, go to next
step.
7) Turn ignition off. Disconnect Central Timer Module (CTM).\
CTM is mounted behind right corner of dash, beside glove box. Turn