Dodge RAM 1500 1998 Owner's Manual page 411

8E - 4 ELECTRONIC CONTROL MODULES
ENGINE CONTROL MODULE (Continued)
NOTE: ECM Inputs:
• Accelerator Pedal Position Sensor (APPS) Volts
• APPS1 Signal — For off engine APPS
• APPS2 Signal — For off engine APPS
• APPS idle validation switches #1 and #2
• Battery Temperature
• Battery voltage
• Camshaft Position Sensor (CMP)
• CCD bus (+) circuits
• CCD bus (-) circuits
• Crankshaft Position Sensor (CKP)
• Data link connection for DRB scan tool
• Engine Coolant Temperature (ECT) sensor
• Fuel pressure sensor
• Fan speed (engine cooling fan)
• Ground circuits
• Inlet air temperature sensor/pressure sensor
• Intake air temperature sensor/MAP sensor
• Oil Pressure switch
• Power ground
• Sensor return
• Signal ground
• Water-In-Fuel (WIF) sensor
NOTE: ECM Outputs:
After inputs are received by the ECM, certain sen-
sors, switches and components are controlled or reg-
ulated by the ECM. These are considered ECM
Outputs. These outputs are for:
• CCD bus (+) circuits
• CCD bus (-) circuits
• CKP and APPS outputs to the PCM
• Data link connection for DRB scan tool
• Fan Clutch PWM
• Five volt sensor supply
• Fuel Control Actuator
• Fuel transfer (lift) pump
• Intake manifold air heater relays #1 and #2 con-
trol circuits
• Malfunction indicator lamp (Check engine lamp)
(databus)
• Oil Pressure Swith/warning lamp (databus)
• Wait-to-start warning lamp (databus)
• Water-In-Fuel (WIF) warning lamp (databus)
REMOVAL
The engine control module (ECM) is bolted to a
support bracket near the fuel filter. The support
bracket mounts to the block with four capscrews and
vibration isolators. A ground wire is fastened to the
bracket. The other end of the wire is fastened to the
engine block.
(1) Record any Diagnostic Trouble Codes (DTC's)
found in the ECM.
To avoid possible voltage spike damage to the
ECM, ignition key must be off, and both negative
battery cables must be disconnected before unplug-
ging ECM connectors.
(2) Disconnect both negative battery cables at both
batteries.
(3) Remove the 50–way and 60–way connector
bolts at the ECM. Note: The connector bolt is a
female allen head. As bolt is being removed, very
carefully remove connectors from the ECM.
(4) Remove five ECM mounting bolts and remove
ECM from the vehicle (Fig. 2).
Fig. 2 Diesel ECM
1 - ENGINE CONTROL MODULE (ECM)
2 - ECM MOUNTING BOLT
3 - 50-WAY CONNECTOR
4 - SUPPORT PLATE
5 - 60-WAY CONNECTOR
INSTALLATION
Do not apply paint to ECM or a poor ground will
result.
(1) Position the ECM to the ECM support bracket
and install the five mounting bolts. Tighten the bolts
to 24 N·m (18 ft. lbs.).
(2) Check pin connectors in ECM, 50–way and
60–way connectors for corrosion or damage. Repair
as necessary.
(3) Clean pins in the 50–way and 60–way electri-
cal connectors with a electrical contact cleaner.
(4) Install the 50–way and 60–way connectors to
ECM. Tighten connector bolts to 3 N·m (27 in. lbs.).
(5) Reconnect both negative battery cables.
(6) Use DRBIII scan tool to erase any stored com-
panion DTC's from ECM.
DR