What Does P1645 Mean?
The powertrain data bus is not receiving expected messages from the all-wheel drive control module. This communication loss prevents proper coordination between the engine management and AWD systems.
Common Causes
35%
Faulty all-wheel drive control module with communication circuit failure
30%
Open or short circuit in CAN bus wiring to AWD module
20%
Corroded or loose connectors at AWD control module
10%
Loss of power or ground to AWD control module
5%
AWD module software corruption or programming error
Diagnostic Steps
1
Step 1: Locate AWD control module and verify power and ground supplies are present
2
Step 2: Check for DTCs stored in AWD module using full system scan
3
Step 3: Inspect AWD module connector for corrosion, moisture, or damaged pins
4
Step 4: Test CAN bus continuity and resistance between ECM and AWD module
5
Step 5: Monitor live CAN data to verify message transmission from AWD module
Estimated Repair Cost
$200 - $1,400
Parts + labor, varies by vehicle and location
The powertrain data bus is not receiving expected messages from the all-wheel drive control module. This communication loss prevents proper coordination between the engine management and AWD systems.
The most common cause of P1645 (Data Bus Powertrain missing message f.all wheel drive contr) is: Faulty all-wheel drive control module with communication circuit failure
Typical repair costs for P1645 range from $200 to $1,400, depending on the vehicle, location, and whether you do it yourself or go to a shop.
All-wheel drive system may be disabled, reverting vehicle to two-wheel drive operation. Traction and stability may be compromised in adverse conditions.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P1645 to identify the root cause.
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Quick Info
Category
Powertrain
System
All-Wheel Drive System Communication
Difficulty
Type
Manufacturer
Recommended Tools
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