What Does C1117 Mean?
C1117 indicates that the ABS/ESC control module is not receiving a valid RPM signal from the engine control module or crankshaft/wheel speed sensor circuit. This code affects the chassis safety systems, specifically the anti-lock braking and traction control functions. The module has detected either no signal, an intermittent signal, or a signal that is out of range from the engine RPM input circuit used for coordinating braking and traction control interventions.
Common Causes
35%
Damaged, corroded, or loose wiring/connectors in the RPM signal circuit between ECM and ABS module
30%
Faulty crankshaft position sensor or wheel speed sensor providing incorrect data to ABS module
20%
Defective ABS/ESC control module unable to properly process RPM input signal
10%
Communication fault between ECM and ABS module on CAN bus network
5%
Low battery voltage or charging system fault causing signal degradation
Diagnostic Steps
1
Step 1: Perform visual inspection of all wiring harnesses and connectors between the ECM and ABS module, checking for damaged wires, corrosion, loose connections, or chafing. Pay special attention to connectors near wheel wells and underbody areas exposed to road debris and moisture.
2
Step 2: Using a digital multimeter, measure battery voltage at the ABS module (should be 12-14V engine off, 13.5-14.8V engine running). Check ground connections at both ECM and ABS module for resistance (should be less than 0.5 ohms to chassis ground).
3
Step 3: Monitor live data stream for RPM signal at both the ECM and ABS module simultaneously while engine is running. Compare readings to verify if signal is being generated by ECM but not received by ABS module, indicating a communication issue.
4
Step 4: Test crankshaft position sensor output voltage/waveform with oscilloscope or multimeter while cranking engine (typically should produce AC voltage 0.3-3V or digital square wave depending on sensor type). Verify sensor air gap and mounting if applicable.
5
Step 5: Check CAN bus communication between modules using scan tool bi-directional controls or multimeter to measure CAN High and CAN Low voltage levels (should be approximately 2.5V at rest, oscillating between 2.0-3.5V during communication).
6
Step 6: Clear codes and perform test drive including ABS activation to verify repair. Monitor for code return and confirm ABS/traction control warning lights remain off during normal operation and hard braking events.
Estimated Repair Cost
$100 - $800
Parts + labor, varies by vehicle and location
C1117 indicates that the ABS/ESC control module is not receiving a valid RPM signal from the engine control module or crankshaft/wheel speed sensor circuit. This code affects the chassis safety systems, specifically the anti-lock braking and traction control functions. The module has detected either...
The most common cause of C1117 (RPM Input Circuit Failure) is: Damaged, corroded, or loose wiring/connectors in the RPM signal circuit between ECM and ABS module
Typical repair costs for C1117 range from $100 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Vehicle is generally safe to drive with normal braking function intact, but ABS, traction control, and stability control systems may be disabled or function improperly. Exercise increased caution in wet or slippery conditions and repair within a few days to restore full safety system functionality.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1117 to identify the root cause.
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Quick Info
Category
Chassis
System
Anti-lock Braking System (ABS) / Electronic Stability Control (ESC)
Difficulty
Type
Manufacturer
Recommended Tools
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