NO DATA TO DIAGNOSTIC DATA READER
10.5 NO DATA TO DIAGNOSTIC DATA READER
Before using this procedure, all basic mechanical checks and physical inspections should have
been performed with no problem found. Also the diagnosis of the DDEC system in Section 9
referred you to this section.
Read Codes on the Check Engine Light
Perform the following steps to read the codes on the CEL or SEL:
1. Unplug the DDR.
2. Ignition should be ON; engine not running.
3. Enable diagnostic request switch.
4. Read codes flashing on the CEL and SEL.
[a] If codes are flashing out, refer to section 10.5.4.
If you wish to bypass diagnosis of a potential data line of the DDR problem for now,
diagnose the active code by referring to the section that matches the code number.
[b] If CEL and SEL are not flashing out codes, refer to section 10.5.2.
Check Diagnostic Request Circuit
Perform the following steps to check the diagnostic request circuit:
1. Ensure ignition is ON.
2. Plug in DDR.
3. Select Calibration Configuration.
4. Determine port assigned to Diagnostic Request on the ECM input switches.
5. Go to switch light status.
6. Depress and hold the diagnostic request switch.
7. Read status of diagnostic request.
[a] If the switch reads OFF, the diagnostic request circuit (#528) is open or the ground is
poor or open. Repair the open wire or the bad ground. Refer to section 10.5.8.
[b] If the switch reads ON, refer to section 10.5.3.
Check ECM Connectors
Follow this procedure to check the ECM connectors:
All information subject to change without notice.
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION