P0646
Read the instructions below then
start the fault diagnostic procedure.
Symptom: A/C not working. No cooling.
A/C Relay Circuit. Short to Ground/Open.
Fault symptoms
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A/C not working. No cooling.
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On-Board Diagnostics
Type of diagnosis:
Enable criteria:
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Battery voltage should be 10.2-15.8 V.
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Fault criteria:
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The voltage on the input is less than 20% of the battery voltage for more than 3.5 s. (Battery voltage x 0.2 = fault criterion.)
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Dependents:
System reaction to a fault:
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No cooling available and engine management system ignores A/C request from DICE.
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OK report:
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The voltage on the input is greater than 20% of the battery voltage for more than 3.5 s. See fault criteria
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Fault handling:
(See section
Fault handling III, other emissions-related components and functions
for more information)
Diagnostic help
Fault diagnosis concerns an electrical fault in connecting leads or in the sensor.
Functions in the diagnostic tool related to the fault:
See also the description of activations under
"Activate" menu
for more information.
Checking the wiring
Jiggle the wiring harness at several points and in different directions to detect intermittent breaks and short circuits. Observe the multimeter, diagnostic tool or test lamp during the check.
