DDEC III/IV Single ECM Troubleshooting – Section 65.3 Troubleshooting Flash Code 65

Section 65.3
Troubleshooting Flash Code 65

For diesel engine troubleshooting of Flash Code 65, refer to "65.4.1 Multiple Code Check" . The following procedure will troubleshoot Flash Code 65, gasoline engines:‪

Section 65.3.1
Determine System and Failure (Gas Engines)

Determine system and failure as follows:‪

1. Is code 51/0 and is system model year 1997 or older with a 24–volt power supply.
   1. Yes to both — install jumper and refer to "65.3.8 Verify Repairs" .
   2. No to either — for jumper harness already installed, refer to "65.3.2 Check for Voltage" .

Section 65.3.2
Check for Voltage

Perform the following steps to check for voltage.‪

1. Unplug throttle actuator sensor harness connector. See Figure "Series 50 Gas Engine Sensor Harness" .
2. Turn ignition ON.
3. Measure voltage between cavity A and B of the connector.
   1. If the battery voltage reading (12V/24V) is ± 2 volts, refer to "65.3.3 Check for Ground" .
   2. If the voltage is low, refer to "65.3.4 Check for Supply" .
   

   Figure 1. Series 50 Gas Engine Sensor Harness

Section 65.3.3
Check for Ground

Perform the following steps to check for ground:‪

1. Turn ignition OFF.
2. Check ground wire from Cavity B to battery negative (-).
   1. If the ground wire is okay, refer to "65.3.5 Check PWM #2" .
   2. If the ground wire is bad, repair and refer to "65.3.8 Verify Repairs" .

Section 65.3.4
Check for Supply

Perform the following steps to check for supply:‪

1. Turn ignition OFF.
2. Unplug engine sensor harness.
3. Install a jumper between wire cavity A and F of the throttle actuator connector.
4. Measure resistance between cavity R1 and S3, then R1 and T3 at the engine sensor harness.
   1. If both readings are less than 1,000 Ω refer to "65.3.5 Check PWM #2" .
   2. If either reading is greater than 1,000 Ω, it indicates the #561 or #562 wire is open. Repair or replace the wire and refer to "65.3.8 Verify Repairs" .

Section 65.3.5
Check PWM #2

Perform the following steps to check PWM #2:‪

1. Move jumper to cavities E and F at the throttle activator.
2. Measure resistance between cavities R1 and Y1 of the engine sensor harness.
   1. If the measurement is less than 1,000 Ω, refer to "65.3.6 Check Connectors" .
   2. If the measurement is greater than 1,000 Ω, the wire #909 (PWM #2) is open. Repair or replace the wire and refer to "65.3.8 Verify Repairs" .

Section 65.3.6
Check Connectors

Perform the following steps to check the connectors.‪

1. Check both connectors for damaged, bent or broken pins or terminals.
   1. If the connectors are not damaged, refer to "65.3.7 Check for Short" .
   2. If the connectors are damaged, repair or replace the connectors. Refer to "65.3.8 Verify Repairs" .

Section 65.3.7
Check for Short

Perform the following steps to check for a short.‪

1. Remove jumper.
2. Measure resistance between cavity Y1 and R1 on the engine sensor harness.
3. Measure resistance between Y1 and T3 of the engine sensor harness.
   1. If the measured resistance is less than 1,000 Ω, the wires are shorted to each other. Repair or replace the wires and refer to "65.3.8 Verify Repairs" .
   2. If the measured resistance is greater than 1,000 Ω, troubleshooting is complete. Review this section or contact Detroit Diesel Technical Service to replace the actuator. Refer to "65.3.8 Verify Repairs" .

Section 65.3.8
Verify Repairs

Perform the following steps to verify repairs.‪

1. Connect all connectors.
2. With the ignition ON, plug in the DDR and clear the codes.
3. Throttle the engine through various speeds (r/min).
4. Shut the engine off.
5. Turn ignition ON.
6. Read the logged codes.
   1. If no codes are logged, troubleshooting is complete.
   2. If code 65 is logged with any other codes, troubleshooting is complete. Review this section or contact Detroit Diesel Technical Service.