Recall 20V739 affects 11 2020-2021 Peterbilt 520 vehicles for incorrect stability-control brake relay plumbing. Repair is free at any franchised Peterbilt dealer.
Peterbilt is recalling 11 2020-2021 520 vehicles because the stability control brake relay has the Spring Brake Modulating valve or lift axle hose connected incorrectly. During a stability control event, the defect can apply lift axle brakes or modulate park brake chambers, which can de-stabilize the vehicle and increase crash risk; Peterbilt dealers will correct the connections free of charge.
Does this recall apply to your specific vehicle?
The official, free per-VIN recall check is run by NHTSA. Enter your VIN and we'll forward you directly — and add you to a free watchlist so you hear about new recalls for your vehicle.
Check my VIN at NHTSARecallNotify doesn't check your VIN — NHTSA's official tool does. We use your email only to alert you to new recalls.
Watch this vehicle for recalls
Add it to your free watchlist and we will alert you as new federal recalls are posted for your year, make and model. New-recall alerts are rolling out now.
You are on the watchlist.
We will email you as new federal recalls are posted for your vehicle.
What's wrong?
The stability control brake relay on the 2020-2021 Peterbilt 520 is part of the brake system that helps the truck keep control during a stability event. It routes air pressure signals to the right brake valves so the system can apply or release brake force as designed. On trucks with a Spring Brake Modulating valve or liftable axle equipment, the hose routing matters because those valves depend on the correct control signal.
On affected 520 trucks, the Spring Brake Modulating valve control line or the lift axle hose is connected to the wrong place at the stability control brake relay. Instead of receiving the intended control signal, the valve receives pressure from the wrong relay port. That mis-plumbing changes how the brake relay communicates with the spring brake or lift axle circuit, so stability control braking is not managed as designed.
There is no warning sign before failure. The issue is in the air-line routing, so a driver is not given a clear sound, warning light, or pedal feel that identifies the incorrect connection before the system is called on.
Who's affected?
The year changes, but the listed component does not: electronic stability control.
| 2020 Peterbilt 520 | Electronic stability control (esc) |
|---|---|
| 2021 Peterbilt 520 | Electronic stability control (esc) |
| Units affected | 11 |
| Field incidents | NHTSA has logged 1 field incident to date. |
A matching year and model does not guarantee inclusion. Check your VIN to confirm whether your specific truck is included.
What's the safety risk?
During a stability control event, the system can apply lift axle brakes or modulate park brake chambers instead of only the ABS controlled wheel ends. That brake action can destabilize the vehicle and increase crash risk. Schedule the inspection soon, and drive cautiously until it is done. Repair is free at any franchised Peterbilt dealer.
What should I do?
- Check your VIN to confirm your 2020-2021 Peterbilt 520 is included in this recall.
- Contact a franchised Peterbilt dealer to schedule the free chassis inspection and brake relay plumbing correction for the incorrect stability-control hose connection.
- Bring the recall notice if Peterbilt mailed one. If not, reference recall number 20V739 when you call.
- Ask the dealer whether the truck needs operating limits before the inspection, especially if stability-control or brake behavior feels abnormal.
What happens at the repair
At the dealer, a Peterbilt technician inspects the suspect chassis and checks the stability control brake relay plumbing. If the Spring Brake Modulating Valve or lift axle hose is connected incorrectly, the technician corrects the plumbing. The inspection and any needed correction are free under the recall, with parts and labor covered. PACCAR has a general reimbursement plan on file for this campaign. If you already paid for a related brake relay plumbing repair before the owner notice, ask Peterbilt customer service or the service desk how to submit repair documentation under that plan.
| Reimbursement | Reimbursement available |
|---|
Timeline
| November 25, 2020 | NHTSA published the recall |
|---|---|
| December 31, 2020 | Dealer notification began |
| December 31, 2020 | Dealer notification ended |
| January 22, 2021 | Interim owner notification (was planned for this date) |
| January 25, 2021 | Owner notification mailed |
Frequently asked questions
What is recall 20V739?
Recall 20V739 covers 11 2020-2021 Peterbilt 520 vehicles with stability-control brake relay plumbing that can be connected incorrectly. During a stability-control event, the wrong connection can affect lift axle brakes or park brake chambers and increase crash risk. Peterbilt dealers will inspect and correct the plumbing for free.
What should I do if my 2020-2021 Peterbilt 520 is on this recall?
Check your VIN to confirm your specific vehicle is included in recall 20V739. If it is, contact a franchised Peterbilt dealer to schedule the brake relay plumbing inspection. Reference recall number 20V739 or Peterbilt recall number 20PBF when you call. The repair is free.
Is the recall repair free?
Yes. Federal recall law requires the manufacturer to repair the defect at no cost. For recall 20V739, Peterbilt dealers will inspect the suspect chassis and correct the brake relay plumbing if needed, free of charge.
What is the safety risk?
The safety risk is loss of stability during a stability-control event. The brake relay plumbing error can route braking action to the lift axle brakes or park brake chambers instead of only the ABS-controlled wheel ends, increasing crash risk.
When were owners notified about this Peterbilt recall?
PACCAR issued an interim owner notification on January 4, 2020, and owner notification letters were mailed on January 25, 2021. If you bought the vehicle used or never received a letter, check your VIN and call Peterbilt customer service at 1-940-591-4220.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/20V739000 |
|---|---|
| Peterbilt customer service | 1-940-591-4220 |
| NHTSA recall # | 20V739 |
| NHTSA recall # (full) | 20V739000 |
Source documents
-
Download Quarterly Report (PDF) - Download Recall Document (PDF) (PDF)
- Download Recall Document (PDF) (PDF)
- Download Owner Notice (PDF)
- Download Recall Report (PDF)
- Download Recall Acknowledgement (PDF)
This article is generated from NHTSA's primary recall filings and reviewed against the source on May 23, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →