Code result
P273D
Gear Shift Control Module A Supply Voltage High
High severity
What it means
The gear shift control module A reports a supply voltage above the operating range.
Is it safe to drive?
No — stop driving
This code points to a problem that can cause damage or affect safety. Avoid driving and have the vehicle diagnosed promptly.
Most likely causes
Alternator regulator failed to limit output
highOne of the most commonly reported causes for this code — check this first.
Load dump transient after disconnecting a heavy load
lowLess common, but worth ruling out after the more likely causes.
Related help
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