P0645 on Dodge
A/C Clutch Relay Control Circuit
P0645 on Dodge vehicles indicates a/c clutch relay control circuit. Au7o has documented this code across 1 Dodge model — most commonly on Challenger. A general fault in the A/C compressor clutch relay control circuit driven by the control module. The commanded relay state does not match the measured circuit condition.
Common Causes of P0645
- •Faulty A/C clutch relay
- •Open or short in the relay control circuit
- •Corroded/damaged connectors
- •Blown fuse
- •Internal PCM driver fault
P0645 on Dodge by Model
Dodge Challenger(1 issue)
- Dodge Challenger Engine Stalls / Shuts Off While Driving (Alternator & TIPM/Fuel-Pump-Relay Failure)2008-2014
The Dodge Challenger has a well-documented tendency to stall or shut off completely without warning while driving — a top-3 engine-category complaint at NHTSA and one of the most-reported electrical/engine problems at CarComplaints. There are two primary, separately documented root causes that present the same symptom. (1) ALTERNATOR FAILURE (3.6L Pentastar, and later 5.7L/6.4L with electro-hydraulic power steering). Chrysler began investigating stalling complaints on 2011-2012 Dodge Chargers in August 2014 and found thermal fatigue of the silicon diodes inside the alternator. The large, intermittent current draw of the electro-hydraulic power-steering (EHPS) pump thermally stresses the diodes until the alternator fails suddenly. This became NHTSA recall 14V634 (Chrysler P60), covering ~434,000 2011-2014 Chrysler 300, Dodge Charger, Challenger, Durango, and 2012-2014 Jeep Grand Cherokee vehicles with the 3.6L engine and 160-amp alternator (remedy began Feb 27, 2015). It was later expanded under NHTSA recall 17V435 (remedy began Feb 12, 2018) to additional 2011-2014 cars with EHPS and 5.7L or 3.6L engines. NHTSA's stated consequence for both: "If the alternator fails, the vehicle may stall without warning, increasing the risk of a crash," with an additional risk of an underhood fire from a short circuit. (2) TIPM (Totally Integrated Power Module) / FUEL-PUMP-RELAY FAILURE (2008-2014, all engines). The TIPM is the car's central fuse/relay/electrical-distribution computer. When it (or its internal fuel-pump relay) degrades, owners report the engine stalling or shutting off mid-drive, intermittent no-starts, flickering lights, and multiple simultaneous warning lights (check engine, traction control/ESC, ABS). CarComplaints documents this on the 2009 Challenger ("engine shuts down while driving," 7 complaints, severity 8.6/10, ~$800 average repair, ~43,300 miles) and the 2013 Challenger ("bad TIPM," 12 complaints, severity 7.2/10, ~$940 average repair, ~43,050 miles). Because the engine quits unexpectedly, the driver loses power steering and (on automatics) power braking assist while the car is in motion — making this a genuine safety hazard, especially in intersections, on highway merges, and during turns. Multiple NHTSA complaints describe near-crashes and crashes from sudden loss of power.
Looking for P0645 on a different make?
View P0645 across all makes →Frequently Asked Questions
What does P0645 mean on Dodge?▼
P0645 stands for "A/C Clutch Relay Control Circuit." A general fault in the A/C compressor clutch relay control circuit driven by the control module. The commanded relay state does not match the measured circuit condition. On Dodge specifically, this code is documented across 1 model.
What causes P0645 on Dodge vehicles?▼
Common causes on Dodge: Faulty A/C clutch relay, Open or short in the relay control circuit, Corroded/damaged connectors, Blown fuse, Internal PCM driver fault. Specific causes vary by model and year — see the per-model sections below.
How much does it cost to fix P0645 on a Dodge?▼
Repair costs vary widely depending on the root cause and specific Dodge model.
Which Dodge models have P0645 documented?▼
Au7o has documented P0645 on 1 Dodge model: Challenger.