Battery voltage at pin 20, 21, 22,
and 23 of actuator harness
connector (relative to return pins
9, 25, and 27 of the actuator
harness connector) fell below 6.2
VDC for a fraction of a second...
OR... electronic control module
(ECM) was not allowed to power
down correctly (retain the battery
supply voltage for 3 seconds) after
keyswitch “OFF”.
Possibly no noticeable performance effects or
possibility of the engine dying or difficulty in
starting the engine.
Circuit Description:
The ECM receives constant voltage from the batteries through the unswitched battery wires that are connected directly
to the positive (+) battery post. There are two in-line 15 Amp fuses in the unswitched battery wires to protect the engine
harness from overheating. The ECM receives switched battery input through the vehicle keyswitch wire, when the vehicle
keyswitch is turned “ON.” The battery return wires are connected directly to the negative (-) battery post.
Component Location:
The ECM is connected to the battery by the actuator harness. This direct link provides a constant power supply for the
ECM. The location of the battery will vary with the OEM. Refer to the OEM Manual.
Shop Talk:
• Examine the injector pigtail nuts, and make sure they are tightened down to the proper torque. Confirm that the pigtail
nuts and solenoid posts do not have damaged threads.
• If the ECM unswitched battery supply is taken from the starter, check for low voltage during cranking. Low voltage
during cranking can cause the ECM power supply to drop below specifications and log Fault Code 434.
• Optimally, the unswitched battery supply for the ECM can be wired directly to the battery.
The injector solenoids receive high voltage when the engine is operating. Do not wear jewelry or damp clothing, and do
not touch the injector solenoids or the solenoid wires when the engine is operating. This can result in electrical shock
that can cause personal injury or death.
CAUTION
To avoid pin and harness damage, use the following test leads when taking a measurement:
Part Number 3822758 - male Deutsch/AMP/Metri-Pack test lead
Part Number 3823996 - female Weather-Pack test lead.
CAUTION
To avoid damaging a new ECM, all other active fault codes must be investigated prior to replacing the ECM.
STEPSSPECIFICATIONSSRT CODE
STEP 1:Read the fault codes.
STEP 1A:Read the fault codes.No active or inactive injector fault
codes
STEP 2:Check the batteries and the power connector.
STEP 2A:Inspect the 3-pin power connector.No damaged pins or loose
connections
STEP 2B:Check the resistance of the battery
supply circuit.
STEP 2C:Check the battery voltage.Normal conditions: At least 12 VDC;
STEP 2D:Check the battery voltage.Connections are tight and corrosion
• Read the fault codes using Compulink™, Part
Number 3823549, Echek™, Part Number
3824437, or INSITE™, Part Number 3824638.
OK
No active or inactive injector fault codes
NOT OK
Troubleshoot the injector fault codes. Refer to
the appropriate injector fault code tree.
STEP 2:Check the batteries and the power connector.
STEP 2A:Inspect the 3-pin power connector.
Condition:
• Turn keyswitch "OFF".
• Disconnect the actuator harness from the battery at the 3-pin connector.
ActionSpecification/RepairNext Step
inspect the 3-pin power connector for:
• bent or broken pins
• pushed back or expanded pins
• corroded pins
• moisture in or on the connector
• missing or damaged seals.
OK
No damaged pins or loose connections
NOT OK
Repair the 3-pin connector. Refer to Procedure
019-2010 and 019-202 in the Troubleshooting
and Repair Manual, Industrial CELECT™ Plus
System Bulletin 3666130.
• Place positive (+) probe of the multimeter on
the positive (+) battery terminal, and touch
negative (-) probe to the negative (-) battery
terminal while trying to start engine.
OK
Normal conditions: At least 12 VDC; During
cranking: At least 6.2 VDC
NOT OK
Charge or replace the battery. Refer to the
OEM Troubleshooting and Repair Manual.
2D
5A
STEP 2D:Check the battery voltage.
Condition:
• Turn keyswitch "OFF".
ActionSpecification/RepairNext Step
check the battery voltage.
• Check the battery terminal connections on both
positive (+) and negative (-) terminals.
OK
Connections are tight and corrosion free
NOT OK
Tighten the loose connections, and clean the
terminals. Refer to the OEM Troubleshooting
and Repair Manual.
STEP 4A:Inspect the harness and the ECM connector pins.
CAUTION
To avoid damaging a new ECM, all other active fault codes must be investigated prior to replacing the ECM.
Condition:
• Turn keyswitch "OFF".
• Disconnect the actuator harness connector from the ECM.
ActionSpecification/RepairNext Step
inspect the harness and the ecm connector pins
for:
• bent or broken pins
• pushed back or expanded pins
• corroded pins
• moisture in or on the connector
• missing or damaged seals.
OK
No damaged pins
NOT OK
Repair the damaged pins. Repair or replace
the engine harness, connector, or ECM,
whichever has the damaged pins.
• Repair the engine harness. Refer to
Procedure 019-203 in the Troubleshooting
and Repair Manual, Industrial CELECT™
Plus System Bulletin 3666130.
• Replace the engine harness. Refer to
Procedure 019-043 in the Troubleshooting
and Repair Manual, Industrial CELECT™
Plus System Bulletin 3666130.
• Replace the ECM. Refer to Procedure
019-031 in the Troubleshooting and Repair
Manual, Industrial CELECT™ Plus System
Bulletin 3666130.
• Replace the o-ring on the 28-pin connector
if it is damaged or missing. Refer to
Procedure 019-203 in the Troubleshooting
and Repair Manual, Industrial CELECT™
Plus System Bulletin 3666130.
STEP 4B:Check for an open circuit in the battery power circuits.
CAUTION
To avoid pin and harness damage, use the following test lead when taking a measurement:
Part Number 3822758 - male Deutsch/AMP/Metri-Pack test lead.
Condition:
• Turn keyswitch "OFF".
• Disconnect the actuator harness connector from the ECM.
ActionSpecification/RepairNext Step
check for an open circuit in the battery power
circuits.
• Measure the voltage from pin 20 to pin 9 of the
actuator harness.
• Measure the voltage from pin 21 to pin 25 of the
actuator harness.
• Measure the voltage from pin 22 to pin 27 of the
actuator harness.
• Measure the voltage from pin 23 to pin 9 of the
actuator harness.
OK
10 to 15 VDC
NOT OK
Repair or replace the engine harness. Refer to
Procedure 019-203 or 019-043 in the
Troubleshooting and Repair Manual, Industrial
CELECT™ Plus System Bulletin 3666130.
• Check from negative (-) battery post to block
ground.
• Check from block ground to negative (-) starter
OK
Meets OEM specifications for voltage drop
under electrical load
4F
post ground.
• Check block to frame ground.
• Check block to cab ground.
NOT OK
Repair vehicle grounds.
5A
STEP 4F:Check the injector solenoid captive nuts for proper torque.
WARNING
The injector solenoids receive high voltage when the engine is operating. Do not wear jewelry or damp clothing, and
do not touch the injector solenoids or the solenoid wires when the engine is operating. This can result in electrical
shock that can cause personal injury or death.
Condition:
• Turn keyswitch "OFF".
ActionSpecification/RepairNext Step
check the injector solenoid captive nuts for proper
torque.
• Remove the valve covers and check the injector
OK
Captive nuts are correctly torqued
5A
solenoid captive nuts for proper torque.
NOT OK
5A
Tighten the captive nuts. Replace the valve
covers.