PLATE 1P6167 - Caterpillar

Use this procedure in order to troubleshoot the air inlet heater or use this procedure if any one of the diagnostic codes in Table 1 is active or logged.
Table 1
Diagnostic Codes Table
Code and Description Conditions which Generate this Code System Response
617-5 Inlet Air Heater Relay current below normal The Electronic Control Module (ECM) detects a current flow that is below normal during an attempt to energize the air inlet heater relay. The code is latched. The code is logged.
The air inlet heater will be disabled if an open has occurred in the wiring in the circuit. The air inlet heater will be energized continuously if a short to the +Battery has occurred in the wiring in the circuit.
617-6 Inlet Air Heater Relay current above normal The ECM detects excessive current during an attempt to energize the air inlet heater relay. The code is latched. The code is logged.
The air inlet heater will be disabled.
The engine may experience hard starting and/or the engine may emit excessive white smoke. The air inlet heater improves the engine's ability to start when the engine is cold. A reduction of white smoke is also a benefit of the air inlet heater.The ECM activates the air inlet heater via the air inlet heater relay. The air inlet heater is activated according to the following cycles:
Power up cycle
Preheat cycle
Crank cycle
Running cycle
Postheat cyclePower Up Cycle - The ECM activates the air inlet heater for two seconds after the ECM is first powered up regardless of temperature or engine speed.Preheat Cycle - If the coolant temperature is less than 49 °C (120 °F), the ECM activates the air inlet heater for 30 seconds. If the operator attempts to start the engine before the end of the preheat cycle, the ECM will begin using the strategy for the crank cycle.Crank Cycle - When the engine is cranking and the coolant temperature is less than 49 °C (120 °F), the air inlet heater will remain on while the engine is cranking. If the engine fails to start, the ECM will revert to the preheat cycle.Running Cycle - The air inlet heater will remain on after the engine has started. If the coolant temperature does not reach 49 °C (120 °F) within five minutes, the ECM will use the postheat cycle.Postheat Cycle - The air inlet heater will cycle on and off if the coolant temperature is still less than 49 °C (120 °F). The heater will turn on for 30 seconds. Then, the heater will turn off for 10 seconds. This cycle continues for 15 minutes. The cycle ends if the coolant temperature exceeds 49 °C (120 °F).
Illustration 1 g01381734
Schematic for the air inlet heater
The connection of any electrical equipment and the disconnection of any electrical equipment may cause an explosion hazard which may result in injury or death. Do not connect any electrical equipment or disconnect any electrical equipment in an explosive atmosphere.
Illustration 2 g01338263
Typical left side engine view
(1) Air inlet heater relay
(2) Connector for the air inlet heater relay
(3)