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Fault Code 187: Sensor Supply Voltage Number 2 Circuit

The document describes fault code 187 related to low voltage detected on the sensor supply number 2 circuit. The fault can be caused by a short circuit, failed sensor, or failed ECM power supply. Technicians should operate the engine under conditions that cause the fault and unplug sensors one at a time to isolate the root cause.

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13K views2 pages

Fault Code 187: Sensor Supply Voltage Number 2 Circuit

The document describes fault code 187 related to low voltage detected on the sensor supply number 2 circuit. The fault can be caused by a short circuit, failed sensor, or failed ECM power supply. Technicians should operate the engine under conditions that cause the fault and unplug sensors one at a time to isolate the root cause.

Uploaded by

hamilton miranda
Copyright
© © All Rights Reserved
We take content rights seriously. If you suspect this is your content, claim it here.
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File: 70-fc187 Page 1 of 2

Fault Code 187

Sensor Supply Voltage Number 2 Circuit

CODES REASON EFFECT

Fault Code: 187 Sensor Supply Voltage Number 2 Engine will run derated. No engine protection
PID(P), SID(S): S232 Circuit - shorted low. Low voltage for intake manifold air temperature.
SPN: 1080 detected at the sensor supply
FMI: 4/4 Number 2 circuit.
Lamp: Amber
SRT:

Sensor Supply Voltage Number 2 Circuit

Circuit Description:
The Sensor Supply Number 2 pin of the ECM provides (+) 5 VDC for the camshaft position sensor, exhaust gas pressure
sensor, rail fuel pressure sensor, intake manifold pressure sensor, EGR valve position sensor, and EGR differential
pressure sensor.

Component Location:
Sensor Supply Number 2 is located in the ECM.

Shop Talk:
Low voltage on the +5 volt supply line can be caused by a short circuit to ground in a supply line, a short circuit between
a supply line and a return line, a failed sensor, or a failed ECM power supply.
During the fault code response test outlined for each sensor connected to sensor supply number 2, Fault Code 187
must be active before unplugging each sensor. If the fault code is not active, but can be easily duplicated by operating
the engine, the following can be performed:
• Operate the engine under the conditions that will cause Fault Code 187 to become active, even if it logs for a short
period of time, unplug one sensor at a time until Fault Code 187 stops logging under the test conditions. Each sensor
can be unplugged with the engine running. Note: The engine may not start if the camshaft position sensor is
unplugged.

Refer to Troubleshooting Fault Code t05-187


© 2008 Cummins Inc., Box 3005, Columbus, IN 47202-3005 U.S.A. Printed from QuickServe® Online.
All Rights Reserved. Last Modified: 01-Sep-2010
File: 70-fc187 Page 2 of 2

© 2008 Cummins Inc., Box 3005, Columbus, IN 47202-3005 U.S.A. Printed from QuickServe® Online.
All Rights Reserved. Last Modified: 01-Sep-2010

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