Oxygen Sensor Upstream & Downstream 234-4012 234-4018 Compatible for 1999-2002 Chevy
- 1999 to 2002 Silverado, Suburban, Express, Sierra, Yukon, Tahoe
- 4 sensors, upstream and downstream
- Part numbers 234-4012 and 234-4018
- Zirconium sensing material
- Exhaust gas oxygen level monitoring
Last refreshed Oct 2, 2026 · Based on the Amazon listing and published specifications, not hands-on testing.
A four sensor set, upstream and downstream, for a long list of late-nineties Chevy and GMC trucks and SUVs. Confirm engine and sensor position, since the listing does not map each part number.
As an Amazon Associate I earn from qualifying purchases. ProductDome earns a commission when you buy through links on this page.
ASIN: B0GMNVM34CCategory: Oxygen
Overview
Automost supplies this set of oxygen sensors to monitor exhaust gas oxygen on Chevy and GMC trucks and SUVs. The sensing material is zirconium, and the set mixes upstream and downstream sensors.
A four sensor set covers both sides of the catalyst in one purchase, which suits a full replacement. The caveat is mapping: the listing does not say which part number goes where or which engine each fits.
Who it's for
Owners of trucks and SUVs on the list who are chasing emissions faults can replace the full set. Owners of other years, or those needing one sensor, should check the part numbers first.
Pros and cons
- Upstream and downstream sensors
- Four sensors in one purchase
- Wide vehicle list
- Zirconium sensing material
- Part number mapping unclear
- Engine fit not specified
- Thread and connector details missing
- No warranty stated
Performance notes
A zirconium sensor produces a voltage that changes with the oxygen content in the exhaust, and the engine computer uses that signal to adjust the fuel mixture. Upstream sensors guide fueling, while downstream sensors check the catalyst, so positions must match.
Specifications
| Brand | Automost |
|---|---|
| Construction & materials | |
| Material | Zirconium |
| Compatibility & installation | |
| Vehicle fit | 1999-2002 Chevy Silverado, Suburban, Express; GMC Sierra, Yukon; Tahoe |
| Included components | |
| Unit count | 4 Count |
| Other details | |
| Position | Upstream and Downstream |
| Part number | 234-4012, 234-4018 |
| Use | Exhaust gas oxygen level monitoring |
Frequently asked questions
How should I look after these Automost oxygen sensors?
The listing gives no care instructions, so follow the guidance printed in the box or your service manual.
Do they fit a later model Silverado?
No. The title covers 1999 to 2002 only.