PACCAR MX (2004 Emissions) Fault Code: P1137 Lambda Sensor Heater Power Supply – Incorrect

SET CONDITIONS:
The PCI ECU (D420) detects that the power supply to control the lambda sensor heater is less than 9 V for more than five seconds.

DIAGNOSTIC CONDITION:
This diagnostic runs continuously when the engine is running.

RESET CONDITION:
This DTC changes to inactive when the fault is no longer detected.

POSSIBLE CAUSES:
Power supply to the PCI ECU

ADDITIONAL INFORMATION:
The PCI ECU uses the oxygen concentration in the exhaust measured by the lambda sensor (F834) to determine the air/fuel ratio of the combustion process. The sensor has an integrated heater to maintain a sensor operating temperature of approximately 750?C [1382?F].