Improperly installed alarms, stereos, or OBD2 tuning devices interfering with data lines. 2. Symptoms Check Engine Light (MIL) illumination.
Broken, shorted, or corroded wiring in the powertrain CAN bus network.
Automatic transmission stuck in a single gear or "limp mode" (shifting harshly). ABS/Traction Control lights on the dashboard. Slow acceleration or poor takeoff performance. Unexplained "no start" conditions. 3. Diagnostic & Troubleshooting Steps p1648-vw
Check for accompanying codes like P1626 (missing message from TCM) or ABS/TC-related codes.
Using a wiring diagram, check continuity of the high and low CAN Bus wires (usually orange/black and orange/brown) between the TCM and ECM. 4. Typical Fixes Improperly installed alarms, stereos, or OBD2 tuning devices
Repairing broken CAN bus wires.
This is a communication error between ECUs, not necessarily a failed sensor. 1. Common Causes Broken, shorted, or corroded wiring in the powertrain
Secondary Air Injection System Incorrect Flow Detected. P1648. 18056. Data Bus Powertrain Malfunction. Customer. JustAnswer Jeep Grand Cherokee Diesel P0700 P1648 Codes Explained