CM870 and ISX Engines – FAULT CODE 691

Turbocharger Number 1 Compressor Inlet Temperature Sensor Circuit – Voltage Above Normal or Shorted to High Source


Overview

CODE REASON EFFECT
Fault Code: 691
PID: S151
SPN: 1172
FMI: 3/3
LAMP: Amber
SRT: 

Turbocharger Number 1 Compressor Inlet Temperature Sensor Circuit – Voltage Above Normal or Shorted to High Source. High signal voltage detected at the turbocharger compressor inlet air temperature circuit.

Engine will run derated.

Turbocharger Compressor Inlet Air Temperature Sensor Circuit
SMALL | MEDIUM | LARGE

Circuit Description

The turbocharger compressor inlet air temperature sensor is used by the electronic control module (ECM) to monitor the turbocharger compressor inlet air temperature. The ECM monitors the voltage on the signal pin and converts this to a temperature value. The turbocharger compressor inlet air temperature value is used by the ECM for the engine protection system and engine emissions control.

Component Location

The turbocharger compressor inlet air temperature sensor is located on the turbocharger compressor inlet. Refer to Procedure 100-002.

Shop Talk

Beginning with ESN 14039654, the temperature sensor return circuit was separated from the pressure sensor return circuit. For ESNs prior to this and with engine wiring harness Part Number 3682854, see the Common Pressure/Temperature Sensor Return Circuit above. For this ESN and greater or for any other engine wiring harness part number, see the Separate Pressure/Temperature Sensor Return Circuit above.

The turbocharger compressor inlet air temperature sensor shares return wires in the engine harness with other sensors. An open return can cause multiple fault codes to be active. Before troubleshooting Fault Code 691, check for multiple fault codes.

Possible causes of this fault code include:

  • Open return circuit in the harness, connectors, sensor, or ECM
  • Open signal circuit or shorted to a voltage source.

Temperature (°C)
Temperature (°F)
Resistance (ohms)
-10
14
49k to 62k
0
32
29k to 36k
20
68
11.3k to 13.7k
40
104
4.9k to 5.8k
70
158
1.6k to 1.9k
100
212
640 to 720

Refer to Troubleshooting Fault Code t05-691

Last Modified:  22-Oct-2010