DDEC TROUBLESHOOTING
54.3 TROUBLESHOOTING FLASH CODE 54
The following procedure will troubleshoot Flash Code 54.
54.3.1
Test Drive Vehicle
Take the vehicle for a test drive with an assistant.
1. View DDR; select vehicle speed.
[a] If mph reads 0 (zero), or stays steady with the vehicle in motion, refer to section 54.3.2.
[b] If speed appears correct, refer to section 54.3.11.
54.3.2
Speed Sensor Identification
Identify the speed sensor type - type one or type two.
1. The type one sensor is a magnetic pickup and may be located in one of the following
locations: transmission tail shaft, wheel rim, mechanical speedometer cable. If you have a
type one sensor, refer to section 54.3.3. (Verify with DDR signal type - magnetic.)
2. The type two sensor communicates with square wave input and output signals and requires
the ECM to be configured correctly. Refer to section 54.3.12. (Verify with DDR signal
type - switched.)
54.3.3
Check Vehicle Speed Sensor Circuit
Perform the following steps to check the vehicle speed sensor.
1. With ignition off, disconnect the vehicle harness connector.
2. Measure resistance of VSS circuit across vehicle harness connector pins, E2 to E3.
See Figure 54-1.
[a] If the resistance measurement is less than 50 , refer to section 54.3.4.
[b] If the resistance measurement is greater than 3,000
or open, refer to section 54.3.6.
All information subject to change without notice.
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION
54-5
