Section 28.3
Troubleshooting Flash Code 28
The following procedure will troubleshoot Flash Code 28.
Section 28.3.1
Multiple Code Check
Perform the following steps to check for multiple codes.
- Turn vehicle ignition switch ON.
- Plug in DDR.
- Read active codes.
- If code 172/4 was logged and there are no other codes logged, refer to "28.3.2 Sensor Check" .
- If code 172/4 and any of the following codes 110/3, 175/3, 174/3, 72/3 or 102/3 were logged, refer to "90.1 Description of Engine Sensor Harness" .
- If code 172/4 and any code except the following were logged 110/3, 175/3, 174/3, 72/3 or 102/3, refer to "28.3.2 Sensor Check" .
Section 28.3.2
Sensor Check
Perform the following steps to check the sensor.
- Turn vehicle ignition OFF.
- Disconnect the ATS connector. See Figure
"Engine Harness to Air Temperature Sensor Connector"
.
Figure 1. Engine Harness to Air Temperature Sensor Connector
- Start engine and run until Check Engine light comes on, or for eight minutes.
- With engine still running, read active codes.
- If code 172/4 and any other codes were logged, refer to "28.3.4 Check for Short" .
- If 172/3 and any other codes except 172/4 were logged, refer to "28.3.3 Check Air Temperature Sensor Connectors" .
Section 28.3.3
Check Air Temperature Sensor Connectors
Perform the following steps to check the ATS connector.
- Check terminals at the ATS connector (both sensor and harness side) for damage; bent, corroded and unseated pins or sockets.
- If terminals and connectors are not damaged, replace ATS. Refer to "28.3.6 Verify Repairs" .
- If terminals and connectors are damaged, repair/replace wires and refer to "28.3.6 Verify Repairs" .
Section 28.3.4
Check for Short
Perform the following steps to check for a short.
- Turn the ignition OFF.
- Disconnect the engine harness connector at the ECM.
- Measure resistance between sockets N2 and Y2 on the engine harness connector. See Figure "ECM Engine Harness Connector" .
- Measure resistance between socket N2 and a good ground.
- If the resistance measurement between sockets N2 and Y2 and between socket N2 and a good ground is greater than 10 Ω or open, refer to "28.3.5 Check ECM Connectors" .
- If the resistance measurement between sockets N2 and Y2, or N2 and battery negative, is less than or equal to 10 Ω, the signal line #132 is shorted to the return line #452 or battery ground. Repair short. Refer to "28.3.6 Verify Repairs" .
Figure 2. ECM Engine Harness Connector
Section 28.3.5
Check ECM Connectors
Perform the following steps to check the ECM connectors.
- Check terminals at the ECM harness connector (both ECM and harness side) for damage; bent, corroded and unseated pins or sockets, especially N2 and Y2 of the ECM connector.
- If terminals or connectors are not damaged, contact Detroit Diesel Technical Services and refer to "28.3.6 Verify Repairs" .
- If terminals and connectors are damaged, repair them. Refer to "28.3.6 Verify Repairs"
Section 28.3.6
Verify Repairs
Perform the following steps to verify repairs.
- Turn ignition OFF.
- Reconnect all connectors.
- Turn ignition ON.
- Clear codes.
- Start and run the engine for eight minutes.
- Stop engine.
- Read inactive codes.
- If no codes are displayed, troubleshooting is complete.
- If code 172/4 is logged with any other codes, all system diagnostics are complete. Review this section from the first step to find the error.
- If code 172/4 is not logged, but other codes are logged, refer to "9.1 First Step for Diagnosing a Fault Within the DDEC System" .
DDEC III/IV Single ECM Troubleshooting Guide - 6SE497 |
Generated on 10-13-2008 |