OBD-II trouble code
P2162: Vehicle Speed Sensor "A"/"B" Correlation
This is the one speed code that can convict the primary sensor — and the primary sensor is the one feeding your speedometer. So unlike the rest of the family, this fault often has a symptom the driver can see, and checking the speedometer against a known-good reference is a genuine diagnostic step rather than a formality.
Quick facts
- System
- Powertrain
- Category
- Transmission / Speed Sensor
- Severity
- High severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $110 – $2,600
- DIY difficulty
- Intermediate DIY
Browse every code in P2100–P2199, or start from the full code library.
What does P2162 mean?
P2162 sets when the module compares the two vehicle speed sources and finds them disagreeing by more than the tolerance it allows, under conditions where they should have agreed.
Every other code in this group names one channel. This one names both, and that single difference changes where the diagnosis starts. The parent and circuit codes at P2158 through P2161 all concern the secondary channel, and the secondary channel is the quiet one — it does not feed the instrument cluster, so a fault in it produces no visible symptom and gets found during an unrelated scan. P2162 is the only member of the family that can be set by a fault in the primary channel, and the primary channel is the one the driver watches all day. That makes this the code most likely to arrive with an actual complaint attached: a speedometer that reads wrong, sticks at a value, drops to zero, or flickers.
So the first diagnostic step is free and should be done before the bonnet is opened. Drive the vehicle and compare the speedometer against an independent reference. If the speedometer is wrong, the primary source is a strong suspect and you are looking at a different repair than the code number's ordering suggests. If the speedometer tracks correctly, the primary source is probably honest and the disagreement is coming from the secondary side — which returns you to the channel the rest of this family covers. Ten minutes of driving splits the problem in half.
The second thing worth understanding is that the module is not demanding that the two values match. It allows a tolerance band, and on most vehicles that band widens as speed rises, because a small percentage error is a larger absolute error at speed. More importantly, the monitor switches itself off under conditions where disagreement is legitimate. Wheels that are slipping, an anti-lock braking event in progress, a transfer case in low range or with a centre differential locked, a torque converter that has not yet locked up, hard cornering where inside and outside wheels travel different distances — all of these make two speed sources at different points in the driveline read differently while everything is working perfectly, and a sensibly written monitor suspends itself rather than logging nonsense.
That is the most useful fact on this page, because it inverts how the freeze frame should be read. On most codes the freeze frame tells you what conditions caused the fault. Here it tells you what conditions the fault survived. The monitor only ran because the vehicle believed the two sources ought to have agreed, so the captured data describes a moment when disagreement should have been impossible. If the freeze frame shows a steady cruise on a straight road with the converter locked and the code still set, the disagreement is real and mechanical or electrical in origin. If it shows conditions where you would expect the sources to differ, the interesting question becomes why the monitor was enabled at all — which points at a mode signal the module has wrong, such as a transfer case position switch reporting high range when the vehicle is in low.
That last case is worth stating plainly because it is the expensive mistake on this code. It is entirely possible for both speed sensors to be accurate, healthy and correctly reporting, and for P2162 to be completely justified, because the *relationship* between the two measuring points has changed rather than either measurement being wrong. A four-wheel-drive system engaged when the module thinks it is not, a limited-slip or locking differential behaving differently than the strategy assumes, a driveline component between the two measuring points slipping — each produces two honest numbers that disagree. Replacing a sensor in that situation fits a perfectly good part to a vehicle that never had a sensor fault.
A note on naming, because scan tools disagree. Some tools and reference lists render this code as Output Speed Sensor A/B Correlation rather than Vehicle Speed Sensor A/B Correlation. It is the same address and the same monitor; the difference reflects whether the manufacturer takes its speed references from transmission output shaft sensors or from elsewhere in the driveline. Do not treat the two labels as two different codes.
Common causes
- Failing primary speed sensor, which on this code is as likely a suspect as the secondary one
- Failing secondary speed sensor or the circuit feeding it
- Wiring or connector fault on either channel introducing error rather than total signal loss
- Transfer case or four-wheel-drive mode signal wrong, so the monitor runs when disagreement is legitimate
- Centre or limited-slip differential behaving differently than the comparison strategy assumes
- Torque converter clutch slipping, so input and output measuring points genuinely differ
- Worn or damaged tone ring on either channel giving a consistent percentage error
- Internal transmission slip between the two measuring points
- Module holding a calibration that does not match the fitted driveline after a replacement or reflash
- Loss or corruption of the network message carrying one of the two values
- Failed module that generates one of the speed values on vehicles where a source is broadcast rather than measured locally
Symptoms
- Speedometer reading wrong, sticking, dropping to zero or flickering
- Check engine light with a stability or traction control warning alongside
- Cruise control unavailable or cancelling
- Harsh, delayed or hunting gear changes
- Torque converter lockup engaging and releasing repeatedly
- Anti-lock braking or stability system disabled
- Reduced power or a restricted speed on some vehicles
- Fault that only appears in four-wheel drive or low range
- Odometer accumulating distance at an obviously wrong rate
- Speed-dependent steering assist or door locking behaving inconsistently
Diagnostic steps
- 1.Before opening anything, drive the vehicle and compare the speedometer against an independent reference. A wrong speedometer moves the primary source to the top of the suspect list; a correct one moves it to the bottom.
- 2.Read the freeze frame and ask what conditions the monitor ran under. This code sets only when the module expected the two sources to agree, so the captured data describes a moment when disagreement should have been impossible.
- 3.If the freeze frame shows conditions where the sources would legitimately differ, suspect the mode information rather than the sensors — a transfer case or drive mode signal that is wrong lets the monitor run when it should be suspended.
- 4.Scan every module. One channel frequently lives in the transmission or anti-lock braking module, and its own fault memory often names the failing side directly.
- 5.Graph both speed values together on a road test. Watching which one departs from the other, and at what point, identifies the suspect channel far faster than testing either in isolation.
- 6.Note the shape of the error. A constant percentage difference points at a calibration or tone ring tooth count mismatch; an error that grows with speed points at signal quality; a sudden step points at a connection.
- 7.Confirm the vehicle is not in a drive mode that separates the two measuring points, and check any four-wheel-drive or differential lock status signal against what the vehicle is physically doing.
- 8.Inspect the wiring and connectors on both channels, not just the one you expect to be at fault, since either can produce this code.
- 9.Remove and inspect both sensors and their tone rings for debris, wear and damage, comparing the two rather than judging each on its own.
- 10.Check for internal driveline slip between the measuring points — a torque converter that is not locking, or a transmission slipping under load, produces two honest but disagreeing values.
- 11.Confirm the module calibration matches the fitted axle ratio, tyre size and driveline if any control module has been replaced or reprogrammed.
- 12.After repair, verify both values track each other across the full speed range on a road test rather than checking only that the light stayed off.
Repair cost
$110 – $2,600
The range on this code is wide because the fault can be anywhere from a plug to a gearbox, and the diagnosis is what narrows it. Expect $130 to $300 for a proper diagnosis including a road test with both values graphed; that is money well spent here, because the comparison itself is what identifies the suspect channel. A single speed sensor is $130 to $350 fitted. A wheel speed sensor, where one source is derived from anti-lock braking data, is $150 to $400. Wiring and connector repair is $100 to $400. A tone ring behind a shaft or housing is $350 to $900. Module recalibration after a driveline change is $80 to $250 at a shop with the right software. At the top of the range, a torque converter replaced for slip is $900 to $2,600 — but arrive at that conclusion from evidence of slip, not from this code alone.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with vehicle speed sensor replacement preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
This is an intermediate DIY job. It usually involves diagnostic steps, specialty parts, and some careful work in tight spaces. If you have the tools and a service manual or trustworthy video for your specific vehicle, it is achievable in a weekend. Otherwise, a competent independent shop will be faster.