1999 DODGE RAM PCM ground

   Use Scan Tool To Verify VSS

  Signal Is Sent By PCM 




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921 Not Receiving Distance Pulse  Check PCM Software Level; 

 Message From PCM  Use Scan Tool To Verify 

  Distance Pulse Message Is 

  Sent By PCM 




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940 Not Receiving Air Bag Light On Check CCD Bus Connections At

 Message From Air Bag Module  ACM; Check ACM Fuse 




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950 Not Receiving ABS Light On Message Check CCD Bus Connections 

From Anti-lock Brake Control ModuleAt Anti-Lock Control Module;

  Check Anti-Lock Control 

  Module Fuse 




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999 Undefined Error  Record Failure Message; 

  Press RESET Button To 

  Continue Self-Diagnostic 

  Test 










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2) If no DTCs appear, cluster will start a walking segment
test. First, all segments will be illuminated, then each segment in
sequence. If any segment does not illuminate, repeat test to confirm
and replace instrument cluster. When walking segment test is complete,
bulb check will start.
3) If any bulb does not light, remove instrument cluster and
check bulb and bulb holder. See INSTRUMENT CLUSTER under REMOVAL &
INSTALLATION. Ensure bulb holder is properly installed in cluster. If
bulb and bulb holder are okay, replace instrument cluster. If LED does
not light, replace instrument cluster. When bulb check is complete,
gauge actuator test will start.
4) Each gauge needle should stop at 3 calibration points,
then return to relaxed position. If any gauge does not perform as
specified, remove instrument cluster. See INSTRUMENT CLUSTER under
REMOVAL & INSTALLATION. Inspect all connections between printed
circuit board and gauge terminals, repair as necessary. If connections
are okay, replace instrument cluster. Instrument cluster will
automatically exit self-diagnostics when test is complete.

SYSTEM TESTS
NOTE: There are 2 instrument cluster connectors. These connectors
look identical. Identify connector by wire color. See WIRING
DIAGRAMS.
BRAKE WARNING LIGHT INOPERATIVE
1) Ensure parking brake is released. Turn ignition on. If
brake warning light stays on, check and repair hydraulic brake system
as necessary. See appropriate DISC & DRUM article in BRAKES section.
2) If brake warning light does not illuminate when ignition
is on, check fuse No. 17 (10-amp) on Ram Pickup or fuse No. 11 (10-
amp) on Ram Van and Ram Wagon in junction block. Junction block is
located at left end cover of instrument panel. If fuse is okay, go to
next step. If fuse is blown, locate and repair cause of blown fuse.
Install new fuse and recheck system operation.
3) Turn ignition on. Measure voltage between ground and power
side of fuse No. 17 on Ram Pickup or fuse No. 11 on Ram Van and Ram
Wagon. If battery voltage is present, go to next step. If battery
voltage is not present, locate and repair open circuit between to

3) Turn ignition off. Disconnect washer fluid level sensor
connector. Install jumper wire between washer fluid level sensor
connector terminals. Turn ignition on. Low washer fluid level light
should illuminate. Disconnect jumper wire and light should go off. If
light performs as specified, replace washer fluid level sensor. If
light does not perform as specified, go to next step.
4) Turn ignition off. Check continuity between ground and
washer fluid level sensor connector Black wire. If continuity does not
exist, repair open Black wire between washer fluid level sensor and
ground. If continuity exists, go to next step.
5) Ensure washer fluid level sensor is still disconnected.
Turn ignition off. Remove instrument cluster. See INSTRUMENT CLUSTER
under REMOVAL & INSTALLATION. Check continuity between ground and
instrument cluster connector C2 terminal No. 2 (Black/White wire) on
Ram Pickup and terminal No. 9 (Black/Gray wire) on Ram Van and Ram
Wagon. If continuity does not exist, go to next step. If continuity
exists, repair short to ground in White/Black or Black/Gray wire
between instrument cluster and washer fluid level sensor.
6) Check continuity of Black/White wire on Ram Pickup or
Black/Gray wire on Ram Van and Ram Wagon between washer fluid level
sensor connector and instrument cluster connector C2 terminal No. 2 on
Ram Pickup or terminal No. 9 on Ram Van and Ram Wagon. See Fig. 1. If
continuity does not exist, repair open Black/White wire on Ram Pickup
or Black/Gray wire on Ram Van and Ram Wagon. If continuity exists,
replace bulb.
WAIT-TO-START LIGHT INOPERATIVE (RAM PICKUP - DIESEL)
1) Remove and inspect fuse No. 17 (10-amp) in junction block\
.
Junction block is located at left end cover of instrument panel. If
fuse is okay, go to next step. If fuse is blown, locate and repair
cause of blown fuse. Install new fuse and recheck system operation.
2) Turn ignition on. Measure voltage between ground and power
side of fuse No. 17. If battery voltage is present, go to next step.
If battery voltage is not present, locate and repair open circuit
between Power Distribution Center (PDC) and junction block.
3) Disconnect negative battery cable. Remove instrument
cluster. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Check
for battery voltage between ground and instrument cluster connector C1
terminal No. 2 (Dark Blue/White wire). See Fig. 1. Turn ignition on.
If battery voltage exists, go to next step. If battery voltage does
not exist, repair open Dark Blue/White wire between junction block and
instrument cluster.
4) Turn ignition off. Disconnect Powertrain Control Module
(PCM) White connector C2. PCM is located at firewall in right side of
engine compartment. Connector C2 is center connector. Check continuity
between ground and instrument cluster connector C1 terminal No. 8
(Orange/Black wire). If continuity does not exist, go to next step. If\
continuity exists, repair short to ground in Orange/Black wire between
instrument cluster and ground.
5) Install instrument cluster. Connect battery cable. Install
jumper wire between PCM White connector C2 terminal No. 20
(Orange/Black wire) and ground. See Fig. 2. Turn ignition on. Wait-to-
start light should illuminate. If wait-to-start light illuminates, see
appropriate SELF-DIAGNOSTICS article in ENGINE PERFORMANCE section. If
wait-to-start light does not illuminate, see SELF-DIAGNOSTICS.


I - S YSTE M /C O M PO NEN T T E STS

1999 D odge P ic ku p R 1500
1999 ENGINE PERFORMANCE
CHRY - System & Component Testing - Trucks - Diesel
Ram Pickup
INTRODUCTION
Before testing separate components or systems, perform
procedures in BASIC DIAGNOSTIC PROCEDURES - TRUCKS - DIESEL article.
Since many computer-controlled and monitored components set a
diagnostic trouble code if they malfunction, also perform procedures
in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
NOTE: Testing individual components does not isolate short or open
circuits. Perform all voltage tests with a Digital Volt
-Ohmmeter (DVOM) with a minimum 10-megohm input impedance,
unless stated otherwise in test procedure. Use ohmmeter to
isolate shorted or open wiring harness.
AIR INDUCTION SYSTEMS
INTAKE MANIFOLD AIR HEATER SYSTEM
For testing information on intake manifold air heater system,
perform procedures in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS
article.
INTERCOOLER
Cleaning and inspection procedures for intercooler is the
only information available from manufacturer. See INTERCOOLER under
AIR INDUCTION SYSTEMS in REMOVAL, OVERHAUL & INSTALLATION - TRUCKS -
DIESEL article.
TURBOCHARGER
NOTE: Manufacturer does not recommend turbocharger disassembly.
Turbocharger overhaul should be performed only by an
authorized repair facility.
Turbocharger Boost Pressure
Turbocharger boost pressure testing information is not
available at time of publication.
TURBOCHARGER WASTEGATE
See CONTROL ROD ADJUSTMENT under TURBOCHARGER WASTEGATE in
ON-VEHICLE ADJUSTMENTS - TRUCKS - DIESEL article.
COMPUTERIZED ENGINE CONTROLS
POWERTRAIN CONTROL MODULE (PCM)
The PCM is located on firewall at passenger's side rear
corner of engine compartment. See Fig. 1. The PCM power and ground
circuits may be checked by performing specified test. See DTC P0601 in
SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.


I - S YSTE M /C O M PO NEN T T E STS - R W D - G ASO LIN E

1999 D odge P ic ku p R 1500
1999 ENGINE PERFORMANCE
CHRY - System & Component Testing - Trucks & RWD Vans - Gas
Dodge: Dakota, Durango, Ram Pickup, Ram Van, Ram Wagon
Jeep Cherokee, Grand Cherokee, Wrangler
INTRODUCTION
Before testing individual components or systems, perform
procedures in BASIC DIAGNOSTIC PROCEDURES - TRUCKS & RWD VANS -
GASOLINE article. Since many computer controlled and monitored
components set a fault message if they malfunction, also perform
procedures in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
NOTE: Testing of individual components does not isolate possible
shorts or opens in wiring harness of electronically
controlled systems. Perform all voltage tests using a Digital
Volt-Ohmmeter (DVOM) with a minimum 10-megohm input impedance\
unless otherwise instructed in procedure. Use an ohmmeter to
isolate wiring harness shorts or opens.
COMPUTERIZED ENGINE CONTROLS
POWERTRAIN CONTROL MODULE (PCM)
PCM power and ground circuits may be checked by performing
TEST NS-1 in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article. For
PCM location, see PCM LOCATION table.
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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ENGINE SENSORS, SOLENOIDS & SWITCHES
SENSORS
Camshaft Position (CMP) Sensor
See appropriate DTC P0340: NO CAM SIGNAL AT PCM test in SELF-
DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
Crankshaft Position (CKP) Sensor
See appropriate DTC P0320: NO CRANK REFERENCE SIGNAL AT PCM
test in SELF-DIAGNOSTICS - JEEP, TRUCKS & RWD VANS article.
Engine Coolant Temperature (ECT) Sensor
See appropriate DTC P0117: ECT SENSOR VOLTAGE TOO LOW and DTC
P0118: ECT SENSOR VOLTAGE TOO HIGH tests in SELF-DIAGNOSTICS - JEEP,
TRUCKS & RWD VANS article.
Heated Oxygen Sensor (HO2S)
See appropriate DTC for oxygen sensor in SELF-DIAGNOSTICS -
JEEP, TRUCKS & RWD VANS article.

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:

manifold, sends input signal to Engine Control Module (ECM). ECM uses
input signal for controlling fuel control, timing and engine
protection. ECM will lower engine power if boost is too high.
Oil Pressure Sensor
Oil pressure sensor signal is input to Engine Control Module
(ECM). ECM converts signal to pressure value. Value is sent on CCD Bus\
to instrument panel gauge/light. Oil pressure sensor is located on
side of engine block, below ECM. See Fig. 2.
Power Take Off (PTO)
This input is used on vehicles equipped with a Power Take Off
(PTO) unit. When PTO is engaged, Engine Control Module (ECM) will
disable some OBD-II functions.
Water-In-Fuel (WIF) Sensor
WIF sensor is located in bottom of fuel filter/water
separator. See Fig. 2. WIF sensor delivers input signal to Engine
Control Module (ECM) when water exists in the fuel filter/water
separator. As water level increases, resistance across WIF sensor
decreases. ECM compares decrease in resistance to a high water
standard value. When resistance is 30,000-40,000 ohms, ECM will turn
on WATER-IN-FUEL warning light. WATER-IN-FUEL warning light is located
on instrument panel, just below tachometer. ECM monitors input signal
when ignition switch is in the ON position and continues to monitor
input signal until intake manifold air heater post-heat cycle is
complete.
PCM INPUT SIGNALS
A/C Switch
When A/C switch is in ON position, an input signal is
delivered from A/C switch to Engine Control Module (ECM) to indicate
that A/C operation has been requested. Once A/C operation has been
requested, an A/C request signal is delivered to ECM from A/C high-
pressure switch and A/C low-pressure switch. The A/C request signal
indicates evaporator pressure is within proper range for A/C
operation. ECM uses A/C request signal to cycle A/C compressor clutch
by using an A/C clutch relay. A/C clutch relay may also be referred to
as A/C compressor clutch relay. If A/C high-pressure switch or A/C
low-pressure switch opens, A/C request signal will not be delivered to
the ECM. ECM will then open ground circuit for A/C clutch relay and
A/C compressor clutch will be disengaged.
The A/C clutch relay is located in power distribution center
at driver's side front corner of engine compartment, near the battery.
The A/C high-pressure switch is located on discharge line, near A/C
compressor. The A/C low-pressure switch is located on top of
accumulator.
Accelerator Pedal Position Sensor (APPS) Output From ECM
Accelerator Pedal Position Sensor (APPS) is mounted on top
left of engine. See Fig. 2. Sensor provides DC voltage input signal to
Engine Control Module (ECM) to indicate throttle position. On previous\
engines, there were linkages between accelerator pedal, throttle
position sensor and injection pump. On this engine, no linkage exists
between accelerator pedal and injection pump. APPS signal is sent on
CCD Bus circuit from ECM to PCM.
Automatic Shutdown (ASD) Relay
A 12-volt input signal is delivered from ASD relay to Engine
Control Module (ECM) when ASD relay is energized. If ECM does not
receive a 12-volt input signal when ASD relay is energized, a
Diagnostic Trouble Code (FTC) will be stored in ECM. ASD relay is