The DDEC III/IV engine sensor harness for vehicle engines was originally equipped with five metal retaining clips and was secured to the engine cylinder block with bolts. Effective with engines built in May of 1995, three of the metal clips were replaced by three plastic push-in clips. See Figure
"Typical DDEC III/IV Engine Sensor Harness"
.
Due to a hardware change made in October of 1995 to the DDEC®
III ECM, a path to ground can arise during ECM powerdown which may allow unintended engine cranking.
Unintended engine cranking can occur if all
of the following conditions exist:
The engine has an ECM manufactured between October of 1995 and September of 1996.
The engine is equipped with the Optimized Idle™
feature.
The ignition remains turned on while battery power is removed from the ECM during servicing.
Note: This condition will not occur on engines manufactured after September of 1996.
To address this concern and eliminate the potential for unintended engine cranking under the conditions listed above, an Optimized Idle Starter Relay Harness Overlay Service Kit was released for engines with ECM's manufactured between October of 1995 and September of 1996.
Section 9.6.1 Diagnostic Procedures
Basic mechanical checks should be made beforehand to verify that the problem is definitely related to the electrical portion of the system. If the basic mechanical checks fail to locate the problem, refer to the Detroit Diesel Single ECM Troubleshooting Manual,
(6SE497). Start by reading the "Basic Knowledge Required" section before attempting to diagnosis electrical faults.
Section 9.6.2 Repair and Replacement of DDEC III/IV Engine Sensor Harnesses
If the engine has metal and plastic harness clips:
Remove the bolts securing the metal harness clips to the engine.
The plastic harness clips do not require removal from the engine. Open the clips by inserting a tool such as a flat blade screwdriver into the slot on the side and twist to unhook the clip.
NOTICE:
Do not attempt to remove the plastic harness clips from the engine by pulling or forcing them out with a flat tool. This will damage the clip threads, which may make them unusable.
If removal of the plastic harness attaching clips from the engine is required, unscrew them from the block by rotating them in a counterclockwise direction.
Remove the 30-pin connector from the ECM by loosening the connector attaching bolt. Carefully pull the connector from the ECM and remove the harness from the engine.
Section 9.6.4 Installation of DDEC III/IV Engine Sensor Harness
Install the DDEC III/IV Engine Sensor Harness as follows:
Install the 30-pin connector to the ECM, and torque the connector body attaching bolt to 0.79-1.47 N·m (7-13 lb· in.).
If removal of the plastic harness attaching clips from the engine is required, unscrew them from the bolt holes in the block by rotating in a counterclockwise direction.
If the engine has five metal harness clips:
Install the five bolts securing the metal harness clips to the engine. Torque bolts to 30-38 N·m (22-28 lb·ft).
Section 9.6.5 Installation of Starter Relay Harness Overlay Service Kit
Install starter relay harness overlay service kit on an Optimized Idle option-equipped vehicle engine as follows:
Section 9.6.5.1 Qualifying the ECM for Use with the Starter Relay Harness Overlay Kit
Before installing the starter relay harness overlay service kit, the ECM must
be qualified for use with the kit and replaced, if necessary. Qualify the ECM for use as follows:
Refer to the DDEC III/IV ECM serial number/model number label located on top of the ECM.
If the second letter of the ECM serial number
is "D," "E," or "F" and the last three characters of the modelnumber
are "A01", "A02", "A03", or "A04", the ECM must
be replaced before the kit can be installed. Following is an example of an ECM that must be replaced:
ECM Serial Number
S E
600KZM /ECM Model Number
6DD2368 A03
If the second letter of the ECM serial number
is "A" through "C" or any letter from "G" onward and
the last three characters of the model number
are "C01" through "C03" or "A05" and later alpha-numeric designations, the ECM does not
require replacement before the kit can be installed. Following are examples of ECMs that do not require replacement:
ECM Serial Numbers
SC
6005QM / ECM Model Number
6DD2296CO3 or 6DD2296AO5.
Remove starter relay from relay block (Note: The Check Engine Light
will illuminate once the relay is removed from the relay block, and a code 63 [PWM driver #3 Open Circuit] will be logged).
Measure the voltage between pin 85 of the relay block and a good ground and note the voltage.
If the voltage is less than
4 VDC, pin 85 is PWM # 3. Mark the wire as "PWM # 3" and mark the wire attached to pin 86 of the relay coil as "power".
If the voltage is greater than
4 VDC, pin 85 is the power side of the relay. Mark the wire as "power" and mark the wire attached to pin 86 of the relay coil as "PWM # 3".
Open the hood/cab.
Using the DDR (diagnostic data reader) select "Calibration Configuration," then select ECM inputs and outputs.
Arrow through the selections to find the pin position configured for "Park Brake Interlock."
Locate the appropriate wire in the 30-pin connector and label it "Park Brake Interlock."
Turn off the ignition.
Battery Explosion and Acid Burn
To avoid injury from battery explosion or contact with battery acid, work in a well ventilated area, wear protective clothing, and avoid sparks or flames near the battery. If you come in contact with battery acid:
Flush your skin with water.
Apply baking soda or lime to help neutralize the acid.
Cut the wire labeled "power" from the previous section, refer to step 5
.
Route both of the red wires from the overlay harness to the cut wire.
Cut off any excess wire and strip the insulation.
Splice one of the red wires to the one side of the cut wire.
Splice the other red wire to the other side of the cut wire.
Splice the pink wire (439) to DDEC wire 439.
Route the white wire from the overlay harness through the fire wall to the Optimized Idle park brake interlock input wire located in previous section, refer to step 9
Cut off any excess wire and strip the insulation from the white overlay harness wire.
Splice the white wire into the wire labeled "Digital Input" from the previous section, refer to step 9
, approximately 6 inches from the ECM 30-pin connector.
Install conduit on the section of the white wire in the engine compartment.
Secure conduit.
Close hood/cab.
Replace the starter relay into the relay block.
Section 9.6.8 Verify Installation of Service Kit
Verify installation of service kit as follows:
Battery Explosion and Acid Burn
To avoid injury from battery explosion or contact with battery acid, work in a well ventilated area, wear protective clothing, and avoid sparks or flames near the battery. If you come in contact with battery acid:
Flush your skin with water.
Apply baking soda or lime to help neutralize the acid.
Flush your eyes with water.
Get medical attention immediately.
Reconnect the battery negative (-) cables.
Turn ignition to ON position and wait through bulb check. If "Check Engine" light remains on, check the codes. If a code 63 (PWM driver #3 Open Circuit) is logged, refer to the troubleshooting procedure included below. Otherwise, refer to the Detroit Diesel Single ECM Troubleshooting Manual
(6SE497).
PERSONAL INJURY
Diesel engine exhaust and some of its constituents are known to the State of California to cause cancer, birth defects, and other reproductive harm.
Always start and operate an engine in a well ventilated area.
If operating an engine in an enclosed area, vent the exhaust to the outside.
Do not modify or tamper with the exhaust system or emission control system.
Start the engine.
Toggle the "Cruise" on/off switch from off
to on
. The "Optimized Idle" light should flash.
After the engine shuts down, turn the thermostat on by pressing any button. Press up
or down
arrow until the heat or cool symbol begins to flash.
If the engine starts, repairs are complete.
If the engine does not start,
refer to the Detroit Diesel Single ECM Troubleshooting Manual,
(6SE497).
