What Does C1298 Mean?
The ABS/ESC module (EBCM) has lost communication with the Powertrain Control Module (PCM) over the Class 2 serial data link. This data bus carries critical information between modules including engine torque data, vehicle speed, throttle position, and traction control requests. Without this communication link, traction control is disabled and other cooperative functions between the powertrain and chassis systems are lost.
Common Causes
30%
Class 2 serial data bus wiring fault (open, short to ground, or short to power)
25%
PCM not broadcasting on the data bus due to internal PCM fault or no power
15%
Faulty EBCM serial data interface (receiver circuit failure)
15%
Another module on the data bus pulling the line low (bus contention/short from any module)
15%
Corroded or loose DLC (Data Link Connector) causing bus signal degradation
Diagnostic Steps
1
Check for DTCs in ALL modules, not just the EBCM — if multiple modules show U-codes (communication loss), the data bus itself is faulted. If only the EBCM reports loss of PCM communication, the issue is more isolated.
2
Verify the PCM is powered and functional — check for PCM-related fuses, verify the MIL (check engine light) illuminates during key-on-engine-off bulb check. If the PCM has no power, it cannot communicate.
3
Measure the Class 2 data bus voltage at the DLC with the ignition on — it should show a rapidly toggling signal between approximately 0V and 7V. A fixed voltage (stuck high or low) indicates a bus fault.
4
If the bus is stuck, disconnect modules one at a time while monitoring bus voltage to identify which module is pulling the line. Start with the PCM and EBCM as the most likely culprits for this specific code.
5
Inspect the DLC (OBD-II port) connector pins for damage, corrosion, or pushed-back terminals. Also check for aftermarket devices left plugged into the OBD-II port that may be interfering with bus communication.
Estimated Repair Cost
$100 - $1,200
Parts + labor, varies by vehicle and location
The ABS/ESC module (EBCM) has lost communication with the Powertrain Control Module (PCM) over the Class 2 serial data link. This data bus carries critical information between modules including engine torque data, vehicle speed, throttle position, and traction control requests. Without this communic...
The most common cause of C1298 (PCM Class 2 Serial Data Link Malfunction) is: Class 2 serial data bus wiring fault (open, short to ground, or short to power)
Typical repair costs for C1298 range from $100 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Traction control is fully disabled since the EBCM cannot request engine torque reduction from the PCM. ABS braking typically remains functional as it operates independently. Other cooperative functions (cruise control brake intervention, torque management) will also be offline. The vehicle can be driven carefully, but avoid conditions requiring traction control. Data bus faults can be intermittent — if the fault clears, monitor for recurrence.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1298 to identify the root cause.
OBDHut Mobile App
Scan codes directly from your car with the OBDHut app.
Coming Soon
Quick Info
Category
Chassis
System
Vehicle Communication / ABS / Traction Control
Difficulty
Type
Manufacturer
Recommended Tools
OBD2 Scanner
A quality scan tool helps you read codes, view live data, and clear faults.
