C0055 on 2007-2013 Chevrolet Tahoe: Rear Wheel Speed Sensor Circuit Faults and Fixes

What's Unique About the 2007-2013 Chevrolet TAHOE

For this generation of Tahoe (GMT900), the key issue is that a single sensor on the driveline provides the rear speed signal, which can be confusing for those expecting sensors at the wheels. More importantly, GM has issued a Technical Service Bulletin (TSB #PIP4966B) specifically for these trucks, warning that an internal tone wheel can move on the transfer case output shaft. This changes the air gap to the sensor, creating an erratic signal and triggering code C0055, a unique problem that goes beyond a simple sensor failure. Another extremely common failure point is the sensor's wiring harness chafing through where it passes over the transmission bellhousing, between the engine and firewall.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• ABS warning light is on
• Stabilitrak or Traction Control warning light is on
• "Service Anti-lock Brake System" message in the driver information center
• "Service Stabilitrak" or "Service Traction Control" message
• Cruise control may be inoperative
• Erratic or inoperative speedometer, sometimes dropping to zero only at higher speeds (e.g., above 40 mph)
• Harsh or erratic transmission shifting

Most Likely Causes

1. Faulty Vehicle Speed Sensor (VSS) 🔴 High Probability → Shop Drive Shaft Sensor The sensor is exposed to constant heat from the transmission/transfer case and road debris, leading to eventual electronic failure. It is a very common replacement part.
   How to confirm: Use a scan tool to monitor the rear wheel speed signal. If it's zero or erratic while driving, the sensor is the primary suspect. Resistance for a good sensor is typically between 1,200 and 2,900 ohms when tested with a multimeter. A dynamic test involves checking for a rising AC voltage signal from the sensor as the rear wheels are spun.
   Typical fix: Replace the Vehicle Speed Sensor. It is held by a single bolt (often 13mm) on the transmission tail housing (2WD) or rear of the transfer case (4WD).
   Est. part cost: $25 - $70
2. Damaged Wiring Harness or Connector 🟡 Medium Probability The wiring harness that runs from the sensor up and over the transmission bellhousing is a well-documented chafe point. It frequently rubs against the firewall or transmission case bolts, causing wires to break or short out, which is a very common cause for this code.
   How to confirm: Visually inspect the harness for signs of melting, chafing, or breaks, especially in the tight space between the top-rear of the engine/transmission and the firewall. Check the sensor connector for corrosion, spread pins, or damage. The wires are often Dark Green/White and Purple.
   Typical fix: Repair the damaged section of wire using weatherproof butt connectors and heat shrink. If the connector is damaged, replace the pigtail (e.g., Dorman 645-207 or ACDelco PT2298). 🎬 See this walkthrough on tracing and repairing the VSS wiring harness.
   Est. part cost: $10 - $30
3. Loose Tone Wheel on Transfer Case Output Shaft ⚪ Low Probability → Shop Transfer Case Motor As documented in TSB #PIP4966B, the tone wheel (reluctor ring) inside the transfer case can move on the output shaft, or the shaft itself can have excess movement (end-play). This changes the air gap to the sensor and causes an erratic signal, often setting a C0055 5A code.
   How to confirm: After removing the rear driveshaft and VSS, look into the sensor bore. Use a small screwdriver or pry bar to check for movement of the tone wheel on the shaft. Per the TSB, it should have minimal movement and stay centered in the opening. Excessive in-and-out play of the output shaft itself is also a key indicator.
   Typical fix: This is an advanced, internal transfer case repair. Per the TSB, the fix involves disassembling the transfer case to replace the output shaft bearing and associated snap rings to eliminate the excess play.
   Est. part cost: $50 - $150 for parts, but significant labor

Rare But Worth Checking

• Faulty Electronic Brake Control Module (EBCM): → Shop ABS Control Module The EBCM is the computer that controls the ABS. It can fail internally, but this is rare. All other causes, especially sensor and wiring, should be exhaustively ruled out before condemning the module.
• Metal Debris on Magnetic Sensor Tip: The VSS is magnetic and can collect metallic shavings from normal wear in the transmission or transfer case. A large accumulation can disrupt the signal. Simply cleaning the sensor tip can sometimes resolve the issue, but also indicates potential internal wear.

Diagnosis Steps

1. Connect an ABS-capable scan tool and confirm the presence of C0055. Check for symptom 🎬 Watch: A pro mechanic shows how to properly diagnose GM ABS codes. bytes like '00' (circuit fault) or '5A' (erratic signal) for more clues. '5A' often points towards a mechanical issue like the tone wheel or a wiring short.
2. Use the scan tool's live data function to monitor the 'Rear Wheel Speed' or 'Vehicle Speed Sensor' PID while driving. Look for signal dropouts, erratic readings, or a complete lack of a signal.
3. Perform a thorough visual inspection of the VSS on the transmission/transfer case and its wiring harness. Pay very close attention to the harness section routed over the transmission bellhousing, between the engine and firewall, as this is a primary chafe point.
4. If the signal is bad and wiring looks okay, remove the VSS (one 13mm bolt). Test the sensor's resistance with a multimeter. A reading between 1,200-2,900 ohms is generally considered good.
5. With the sensor removed, inspect the magnetic tip for excessive metal debris.
6. As per TSB #PIP4966B, inspect the tone ring for excessive movement by looking through the sensor mounting hole. Check for both side-to-side and in-and-out play of the transfer case output shaft.
7. If the sensor and tone ring are good, test the wiring harness for continuity and shorts to ground/power from the sensor connector to the EBCM. TSB #PIT4815C references testing circuit 817, which is often a Dark Green wire with a White stripe.
8. If all other components test good, the EBCM may be at fault, but this is the least likely cause.

Parts You'll Likely Need

• Vehicle Speed Sensor (VSS) (OEM #ACDelco 213-4533) — This is the most common component to fail, causing a loss of the rear speed signal.
  Trusted brands: ACDelco, Delphi, Standard Motor Products (SC168), Dorman (917-624)
  OEM price range: $50-$70
  Aftermarket price range: $25-$50
• Vehicle Speed Sensor Connector Pigtail (OEM #ACDelco PT2298) — The connector itself can become brittle from heat or damaged during removal. The wiring is also prone to breaking right at the connector.
  Trusted brands: ACDelco, Dorman (645-207)
  OEM price range: $20-$40
  Aftermarket price range: $10-$25

Related Codes That Often Appear With This One

• P2771 — TSB #PIP4966B notes that C0055 can appear alongside P2771 (Four Wheel Drive Low Switch Circuit). This suggests a related issue within the transfer case or its wiring on 4WD models.

Technical Service Bulletins (TSBs) & Recalls

• PIP4966B: Addresses a Service Anti-Lock Brake System message with DTC C0055, pointing to a possible loose tone wheel or excess movement in the transfer case output shaft.
• PIT4815C: Provides diagnostic information for VSS concerns, including C0055, and notes that scan tool data can be shared over the vehicle's network. It advises on direct circuit testing of circuit 817.

Platform-Specific Known Issues

• TSB #PIP4966B specifically calls out the potential for the tone wheel to move on the transfer case output shaft, or for the shaft itself to have excessive movement, causing an erratic signal.
• The VSS wiring harness is extremely prone to chafing where it passes over the transmission bellhousing and contacts the firewall, a repair that is more common than internal transfer case issues.

Mechanic-Grade Diagnostic Values

• Vehicle Speed Sensor (VSS) Resistance — expected: 1,200 - 2,900 Ohms. Failure: Open loop (OL), near 0 Ohms, or significantly outside the expected range.
• VSS AC Voltage Output — expected: Rises smoothly from <1V AC to over 5V AC as speed increases.. Failure: No voltage, or a jumpy/erratic reading while the driveshaft is turning.
• VSS Signal Frequency (at VSS) — expected: Approximately 25 Hz per 1 MPH (e.g., 250 Hz at 10 MPH).. Failure: No frequency or an erratic frequency reading that doesn't correspond to speed.
• VSS Signal Frequency (at EBCM, Circuit 817 or 1827) — expected: Approximately 1.1 Hz per 1 MPH (e.g., 11 Hz at 10 MPH). This is the converted digital signal from the PCM/TCM.. Failure: Signal drops to zero or is erratic, especially under load, while the raw VSS signal remains stable.

Hidden / Shadow Codes Worth Checking

• C0055 00: Indicates the EBCM has detected a circuit fault, such as an open, a short to ground, or a short to voltage in the rear wheel speed sensor circuit. This points to a wiring or connector issue, or a completely failed sensor. (see via A professional scan tool capable of reading GM-specific ABS/EBCM codes and symptom bytes (e.g., Tech2, GDS2, high-end Autel/Snap-on).)
• C0055 5A: Indicates the EBCM has detected an erratic or implausible signal from the rear wheel speed sensor. This often points to a failing sensor, a loose tone wheel as described in TSB PIP4966B, or an intermittent wiring short. (see via A professional scan tool capable of reading GM-specific ABS/EBCM codes and symptom bytes (e.g., Tech2, GDS2, high-end Autel/Snap-on).)

Wiring & Ground Locations

• VSS Signal Wire (to EBCM) — The signal from the PCM/TCM is sent to the EBCM. Per TSB PIT4815C, this is often Circuit 817 (Dark Green/White). Some service information also references circuit 1827.. This is the final signal path to the brake module. Scoping this wire can determine if the fault is in the sensor/PCM or if the EBCM itself is the problem. A good square wave here with a C0055 code points to a bad EBCM.
• VSS Signal Wire (at I/P Junction Block) — The VSS signal (Dark Green/White wire) can be accessed at the 'Junction Block - Left I/P' under the driver's side dash, specifically at connector X2, pin H1.. This provides an accessible point inside the cabin to test the signal without having to access the EBCM or sensor connectors directly, which can be useful for confirming signal presence from the PCM.
• G103 / G105 — G103 is located at the left rear of the engine compartment on the cowl, above the brake booster. G105 is at the left front of the engine block.. These are primary engine and body grounds. The ECM, BCM, and other modules rely on these grounds. A poor ground at these locations can cause a variety of seemingly unrelated electrical issues, including signal problems that could trigger a C0055.
• G201 — Located at the left end of the dash.. This is a major ground point for the instrument panel cluster and other interior modules. A fault here could disrupt communication or power to the IPC, affecting warning lights and messages related to the C0055 code.

Real Owner Repair Stories

• PerformanceTrucks.net Forums (2007 Silverado, 2WD) — ABS light comes on and C0055 5A is set only during a hard launch from a complete stop. Scan tool shows rear wheel speed drops to 0 MPH during the event, then returns to normal after letting off the throttle.
  ❌ Tried (didn't work) Cleaned EBCM ground, Replaced both speed sensors on transmission, Replaced both front wheel hub/speed sensor assemblies
  ✅ What actually fixed it The user noted that the ECM can get speed data from the TCM over the GMLAN, which can be misleading. The final resolution was not explicitly posted, but the diagnosis pointed to an intermittent failure in the converted signal between the ECM and EBCM under driveline load, suggesting a wiring or terminal connection issue that only manifests when the engine/transmission moves.

OEM Part Supersession History

• GM 19300586 (and others) → ACDelco 213-4533 — Part consolidation and potential design updates over the vehicle's lifecycle.
  Heads up: While listed as an Oxygen Sensor by some vendors, ACDelco 213-4533 is the correct part number for the Vehicle Speed Sensor on this application. Cross-referencing can be confusing.

Model Year Variations Within This Range

• 2007-2008: These model years were typically equipped with a 4-speed automatic transmission (4L60-E/4L65-E).
• 2009-2013: Starting in 2009, the Tahoe was equipped with a 6-speed automatic transmission (6L80). While the function of the VSS is the same, its exact position or the internal components of the transmission/transfer case it reads from may differ slightly.