Allison 3000 & 4000 Gen5 P0642 trouble code:Sensor Reference Voltage “A” circuit low indicate that something wrong in TCM.Here car-auto-repair.com will show you guide on how to solve Allison 3000 & 4000 Gen P0642 problem.
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DIAGNOSTIC RESPONSE:
Default sensor data used
CIRCUIT DESCRIPTION:
This test detects when the 5V reference circuit voltage provided by the TCM and used by certain transmission control components such as the OLS, TFT, analog TPS,and RMR device is detected below specification for a period of time.
ACTION TAKEN WHEN THE DTC SETS:
When DTC P0642 is active, the following conditions occur:
1 The CHECK TRANS light is illuminated.
2 DTC is stored in TCM history.
3 Additional DTCs active depending on 5V reference to function normally.
CONDITIONS FOR CLEARING THE DTC/CHECK TRANS LIGHT:
Use the NEXIQ USB Link 2 diagnostic tool to clear the DTC from the TCM history. The TCM automatically clears the DTC from the TCM history if the vehicle completes forty warm-up cycles without failure.
DTC P0642 may be caused by:
1 Irregular TCM or vehicle power.
2 Poor TCM or vehicle grounds.
3 If multiple DTCs are noted in failure records, this DTC may indicateOEM Transmission unapproved components spliced into W158 or W103, or W103 shorted to chassis ground.
4 W112 or W158 short to ground, high resistance or open.
5 Broken or defective connector assemblies allowing pushed back pins to short together.
6 Unlocked connectors, missing seal plugs allowing moisture in connectors.
DIAGNOSTIC AIDS:
Review applicable information in CONTROL SYSTEM AND TRANSMISSION SPECIFICATIONS to find additional circuit specifications, system and connector diagrams, and troubleshooting tips.
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