Holley EFI Terminator X Wideband Adapter Harness
558-463
The Holley EFI Terminator X Wideband Adapter Harness is a genuine replacement service harness designed specifically for Holley Terminator X and Terminator X Max EFI systems. This adapter harness connects the wideband oxygen sensor to the ECU, restoring factory functionality when replacing a damaged or worn harness.
Featuring dual factory-style connectors, this service harness is manufactured to maintain proper communication between the ECU and the Bosch wideband oxygen sensor for accurate air/fuel ratio feedback, self-learning fuel control, and engine tuning.
Important: This harness is designed exclusively for Terminator X and Terminator X Max systems. Do not use with Holley HP EFI, Dominator EFI, or Sniper EFI systems, as doing so can damage the wideband oxygen sensor and ECU driver circuitry.
Includes:
- (1) Holley EFI Terminator X Wideband Adapter Harness
- (2) Factory-Style Connectors
Specifications
| Specification | Details |
|---|---|
| Manufacturer | Holley EFI |
| Part Number | 558-463 |
| Product Type | Wideband Adapter Harness |
| Part Type | Multi-Purpose Wire Connector |
| Application | Replacement / Service Harness |
| Connector Quantity | 2 |
| Connector Gender | Female |
| Color | Black |
Fitment
| Holley EFI System | Compatibility |
|---|---|
| Terminator X | Compatible |
| Terminator X Max | Compatible |
| HP EFI | Not Compatible |
| Dominator EFI | Not Compatible |
| Sniper EFI | Not Compatible |
Fitment Notes
- Designed exclusively for Holley Terminator X and Terminator X Max EFI systems.
- Replacement service harness for the wideband oxygen sensor connection.
- Do NOT install on HP EFI, Dominator EFI, or Sniper EFI systems.
- Using this harness on incompatible Holley EFI systems can result in wideband oxygen sensor damage and ECU driver failure.
- Verify ECU model before installation.
- Legal for Racing Use Only vehicles.
Tech Insight
1. What does this harness do?
This service harness connects the wideband oxygen sensor to a Holley Terminator X or Terminator X Max ECU, restoring proper communication for air/fuel ratio monitoring and closed-loop fuel control.
2. Can I use this harness on my Holley Sniper EFI system?
No. Holley specifically warns that this harness must not be used with HP EFI, Dominator EFI, or Sniper EFI systems because it can damage both the wideband oxygen sensor and the ECU's wideband driver circuitry.
3. Is this a replacement harness?
Yes. This is a genuine Holley replacement/service harness intended to replace a damaged or worn factory wideband adapter harness.
4. Does this harness include the oxygen sensor?
No. This listing includes only the adapter harness. The wideband oxygen sensor is sold separately.
5. Is this legal for street vehicles?
No. Holley classifies this component as a Racing Use Only part intended exclusively for competition vehicles that are not registered for use on public roads.
