27.3 TROUBLESHOOTING FLASH CODE 27
The following procedure will troubleshoot Flash Code 27.
Perform the following steps to check the sensor.
1. Turn vehicle ignition OFF.
2. Disconnect ATS connector.
3. Install a jumper wire between sockets A and B of the ATS harness connector.
See Figure 27-2.
4. Turn ignition ON.
5. Start and run engine for one minute (ensure oil temp is greater than 140
6. Read active codes.
[a] If code 172/4 or any other codes except 172/3 are logged, refer to section 27.3.2.
[b] If any codes except code 172/4 are logged, refer to section 27.3.4.
Air Temperature Sensor
Check for Short to +5 Volt Line
Perform the following steps to check for a short to the +5 volt line.
1. Turn ignition/engine OFF.
All information subject to change without notice.
6SE497 9709 Copyright © 1997 DETROIT DIESEL CORPORATION