# 89790642T Mercury 115HP DFI PCM | Genuine Used Part

🔧 Product Description

  

Genuine Mercury 115HP DFI / OptiMax PCM - Part Number: 89790642T

  

A genuine Mercury propulsion control module for selected 115HP DFI / OptiMax 1.5L three-cylinder outboards. This PCM manages direct fuel injection, ignition timing, air/fuel control, diagnostics and protection strategy on compatible Mercury and Mariner 115HP DFI engines.

  

⚙️ Key Features

  

• Genuine Mercury PCM / propulsion control module

• Correct Mercury part number 89790642T

• Used on 115HP OptiMax / DFI 1.5L three-cylinder outboards

• Related to Mercury PCM family reference 88555747S

• Requires exact serial-number, calibration and engine-family confirmation before installation

  

🔄 Supersession & Cross Reference

  

OEM Supersession Chain:

  

• 89790642T current PCM reference for listed 115HP DFI applications

  

OEM / Related Numbers:

  

• 89790642T

• 88555747S

• Related PCM family reference: 88555734S

• Related PCM family reference: 88555726S

• Related PCM family reference: 88555703S

• Related 75HP DFI PCM family reference: 89790640T

• Related 90HP DFI PCM family reference: 89790641T

• Related electrical plate reference: 880190T03

• Related braided cable reference: 858414A1

• Related trim harness reference: 819514T18

  

Aftermarket / Verified Equivalents:

  

• No aftermarket equivalent

  

🚤 Compatibility

  

Commonly used on:

  

• Mercury / Mariner 115HP DFI / OptiMax 1.5L three-cylinder outboard electrical systems

  

Typically suits:

  

• Engine models:

• Mercury 115 DFI / OptiMax 1.5L 3-cylinder applications up to serial 1B417701

• Mercury 115 DFI 1.5L 3-cylinder - serial 0T801000 to 1B226999 where PCM 89790642T / 88555747S is specified

• Mercury 115 DFI 1.5L 3-cylinder - serial 1B227000 to 1B417701

• Mariner 115 DFI 1.5L 3-cylinder - serial 1B227000 to 1B417701

• Mercury 115ELPTO / 115 OptiMax electrical plate applications using 89790642T PCM

• Mercury / Mariner 75HP, 90HP and 115HP 1.5L three-cylinder DFI PCM family applications where the exact serial-numbered PCM position specifies 89790642T

  

• HP Range: primarily 115HP for 89790642T calibration

• Engine Type: Mercury / Mariner 1.5L three-cylinder DFI / OptiMax outboard

• Year Range: approximately 2004 - 2006 for the core 115HP DFI serial family, with exact fitment by serial number

• Serial Range: commonly up to 1B417701 for 115HP OptiMax / DFI applications

  

🔌 Function

  

The PCM controls the OptiMax / DFI engine-management system by processing sensor inputs and commanding direct-injection fuel delivery, ignition timing, air compressor strategy, diagnostics and engine-protection functions.

  

Common signs of failure:

  

• No-start with confirmed compressor pressure, fuel pressure and PCM power supply

• No injector or direct-injector command

• No spark command after crank-position and ignition checks

• No communication with diagnostic equipment

• Limp mode, warning horn or protection fault after sensor testing

• Intermittent shutdown or loss of throttle response

• Persistent PCM-related fault codes after wiring and component checks

  

📦 Condition

  

• Genuine used part

• Removed from running engine where applicable

• In good working condition unless otherwise stated

## Details

- **Price:** 650.0 AUD
- **Vendor:** Sawley's Auto and Marine
- **Tags:** Sawley’s AAM Used Parts – Electronic Components | ECU CDI & Electrical Parts

## Variants

| Variant | Price | Available |
|---------|-------|-----------|
| Default Title | 650.00 AUD | In stock |

## Images

- 89790642T Mercury 115HP DFI PCM | Genuine Used Part

---

> Source: [Sawley's Auto and Marine](https://www.sawleysautoandmarine.com.au/products/89790642t-mercury-115hp-dfi-pcm-genuine-used-part)
> Updated: 2026-06-29