What Does C1445 Mean?
This code indicates the vehicle speed signal circuit has failed, meaning the ABS/traction control module is not receiving a valid vehicle speed input. The speed signal is fundamental to all ABS, traction control, and stability control operations as these systems compare individual wheel speeds against overall vehicle speed. Without this signal, the module cannot determine if any wheel is locking or spinning, rendering all active safety systems inoperative.
Safety Warning
Without a vehicle speed signal, ABS cannot calculate wheel slip ratios and traction control cannot detect wheel spin. All active braking safety systems are disabled, and the vehicle may also lose cruise control functionality and experience transmission shift quality issues.
Common Causes
30%
Faulty vehicle speed sensor (VSS) or reluctor ring with damaged teeth or excessive air gap
30%
Open or shorted wiring between the vehicle speed sensor and the ABS module or instrument cluster
25%
Loss of vehicle speed data on the CAN bus due to instrument cluster or PCM communication fault
15%
Corroded or contaminated speed sensor tip causing intermittent or weak signal generation
Diagnostic Steps
1
Step 1: Verify whether the speedometer is functioning correctly. If the speedometer also reads zero while driving, the fault is likely at the speed sensor or its wiring. If the speedometer works but the ABS module reports no speed, the issue is in the signal distribution path.
2
Step 2: Locate the vehicle speed sensor on the transmission output shaft housing or transfer case. Inspect the connector for oil contamination, corrosion, or damage. Transmission fluid leaking past the sensor O-ring is a common cause of connector contamination.
3
Step 3: With the vehicle elevated and a rear wheel spinning by hand, use an AC voltmeter or oscilloscope on the VSS signal wire to verify the sensor generates a clean sine or square wave. Amplitude should increase with speed (typically 0.5-2V AC at low RPM).
4
Step 4: If the speed signal is shared via CAN bus rather than a dedicated wire, check for CAN communication DTCs in the instrument cluster and PCM. Verify CAN bus termination resistance (should read approximately 60 ohms between CAN-H and CAN-L with all modules connected).
5
Step 5: Inspect the reluctor ring (tone wheel) for missing teeth, cracks, or metallic debris accumulation. On vehicles with a magnetic pickup sensor, verify the air gap between the sensor tip and reluctor ring is within specification (typically 0.5-1.5mm).
Estimated Repair Cost
$80 - $500
Parts + labor, varies by vehicle and location
This code indicates the vehicle speed signal circuit has failed, meaning the ABS/traction control module is not receiving a valid vehicle speed input. The speed signal is fundamental to all ABS, traction control, and stability control operations as these systems compare individual wheel speeds again...
The most common cause of C1445 (Speed Vehicle Signal Circuit Failure) is: Faulty vehicle speed sensor (VSS) or reluctor ring with damaged teeth or excessive air gap
Typical repair costs for C1445 range from $80 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
Without a vehicle speed signal, ABS cannot calculate wheel slip ratios and traction control cannot detect wheel spin. All active braking safety systems are disabled, and the vehicle may also lose cruise control functionality and experience transmission shift quality issues.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to C1445 to identify the root cause.
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Quick Info
Category
Chassis
System
ABS / Traction Control / Vehicle Speed System
Difficulty
Type
Manufacturer
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