Recall 20V721 covers 46 2020 Isuzu Npr Hd and Chevrolet Low Cab Forward 4500 trucks for harness and coolant-hose chafing. Repair is free.
Isuzu is recalling 46 2020 Npr Hd and Low Cab Forward 4500 crew cab vehicles because the chassis harness and coolant surge hose can chafe. Leaking coolant or harness damage can lead to a no-start condition, engine stall, or electrical short, which increases crash or fire risk; Isuzu dealers will complete the free repair.
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What's wrong?
On affected 2020 Isuzu Npr Hd and Low Cab Forward 4500 trucks, the issue involves two parts routed near the cab floor: the chassis wiring harness and the coolant return hose from the radiator to the reservoir. The wiring harness carries electrical power and signals along the chassis. The coolant return hose, also called the surge hose, moves engine coolant back to the reservoir so the cooling system can control heat and pressure.
During production with the 6.6-liter gasoline engine, a bracket used on the previous crew cab design was removed. The hose and harness were rerouted to the cab mount bracket, which placed them closer to the cab floor panel. Contact with that panel can rub through the hose or wiring over time. A worn hose can leak coolant, and damaged wiring can create a short circuit.
There is no warning sign before failure. If this recall applies to your VIN, the dealer installs added retention parts and an edge protector, then repairs the hose or wiring as needed.
Who's affected?
Covers both low-cab-forward truck lines, with wiring and cooling-hose components listed for each.
| 2020 Isuzu Npr Hd | wiring |
|---|---|
| 2020 Isuzu Npr Hd | Hoses/lines/piping/fittings |
| 2020 Chevrolet Low Cab Forward 4500 | wiring |
| 2020 Chevrolet Low Cab Forward 4500 | Hoses/lines/piping/fittings |
| Units affected | 46 |
| Field incidents | NHTSA has logged no field incidents to date. |
A matching 2020 Isuzu Npr Hd or Chevrolet Low Cab Forward 4500 does not guarantee inclusion. Check your VIN to confirm whether your specific truck is included.
What's the safety risk?
Engine coolant leaks or a damaged wire harness can leave the truck unable to start, stall the engine, or create an electrical short. A stall raises crash risk, and a short raises fire risk. Schedule the repair soon, and if the truck stalls or will not start, call the dealer. Repair is free at any franchised Isuzu dealer.
What should I do?
- Check your VIN to confirm your 2020 Isuzu Npr Hd or Chevrolet Low Cab Forward 4500 is included in this recall.
- Contact a franchised Isuzu or Chevrolet dealer to schedule the free positive-cable adjustment that keeps the chassis harness and coolant surge hose from chafing.
- Reference recall number 20V721 when you call. Isuzu owners can also use Isuzu recall V2006.
- Bring the recall notice if you have it, and ask the dealer to confirm that parts and labor are covered.
- Stop driving and contact the dealer if you notice coolant leaking, a no-start condition, engine stalling, or electrical short symptoms before the repair.
What happens at the repair
At the dealer, an Isuzu technician adjusts the positive cable on the 2020 vehicles covered by recall 20V721 so the cable is routed away from the chafing area. The recall repair is free, with parts and labor covered. Isuzu says no separate reimbursement plan is needed because the vehicles remained in dealer and body builder inventory, and any vehicles already in customer hands were still within warranty. Ask the service desk how that warranty coverage applies if you already have repair paperwork for this issue.
| Reimbursement | Warranty coverage applies |
|---|
Timeline
| November 20, 2020 | NHTSA published the recall |
|---|---|
| November 20, 2020 | Dealer notification began |
| November 20, 2020 | Dealer notification ended |
| December 11, 2020 | Owner notification mailed |
| December 28, 2020 | VIN-searchable in NHTSA's database — Check your VIN to see whether this recall applies to your specific vehicle. |
| December 28, 2020 | Interim owner notification (was planned for this date) |
Frequently asked questions
What is recall 20V721?
Recall 20V721 covers 46 2020 Isuzu Npr Hd and Low Cab Forward 4500 crew-cab trucks with 6.6L gasoline engines. The chassis harness and coolant surge hose can chafe, leading to coolant leaks, wire damage, a no-start condition, engine stall, electrical short, crash risk, or fire risk.
What should I do if my 2020 Isuzu Npr Hd or Low Cab Forward 4500 is on this recall?
Check your VIN to confirm your specific truck is included in recall 20V721. If it is, contact the appropriate franchised dealer for your vehicle and ask for the recall repair for campaign 20V721. The dealer will adjust the positive cable and complete the covered repair for free.
Is the recall repair free?
Yes. Federal recall law requires the manufacturer to repair the defect at no cost, and the recall remedy says owners will be told the repairs are free. The covered dealer repair includes the needed positive-cable adjustment for affected trucks.
What is the safety risk?
The safety risk is engine coolant leakage, wire-harness damage, a no-start condition, engine stall, or an electrical short. Those conditions increase the risk of a crash or fire. If your VIN is included, arrange the free dealer repair and ask the service desk whether the truck is safe to keep using before the appointment.
More information
| NHTSA campaign page | nhtsa.gov/vehicle-recalls/20V721000 |
|---|---|
| Isuzu customer service | 1-866-441-9638 |
| NHTSA recall # | 20V721 |
| NHTSA recall # (full) | 20V721000 |
Source documents
-
Download Recall Document (PDF) (PDF) - Download Quarterly Report (PDF)
- Download Recall Investigation Document (PDF) (PDF)
- Download Owner Notification Letter (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 24, 2026. RecallNotify does not paraphrase NHTSA's consequence language; that text is reproduced as written above. Editorial standards →