What does P1389 mean on a Ford?

P1389. Glow Plug Circuit High Side Low Input. Applies to F-250/F-350 Super Duty with Power Stroke diesel.

What causes P1389 on a Ford?

Open glow plug high-side feed Failed glow plug relay Burned fusible link Corroded glow plug bus bar Controller fault

How do I fix P1389 on a Ford?

Test glow plug relay operation Check fusible links Measure high-side voltage during glow Inspect the bus bar and connections Replace the relay or repair the feed

Code

P1389

Glow Plug Circuit High Side Low Input

Category: Powertrain - Fuel/Air Metering
Severity: Check Engine Light
Applies to: F-250/F-350 Super Duty with Power Stroke diesel
Related: No single generic twin. See OBD Codes List

Findings, check these first

Open glow plug high-side feed
Failed glow plug relay
Burned fusible link
Corroded glow plug bus bar
Controller fault

Standard procedure

Test glow plug relay operation
Check fusible links
Measure high-side voltage during glow
Inspect the bus bar and connections
Replace the relay or repair the feed

Code lookup

Type a code above, or start from a symptom or a common code.

Press / to jump to the box. Ford-enhanced powertrain, body, chassis and network codes. Generic P0xxx codes live on OBD Codes List.

Sources and review

Review: qualified. Read the source limits below.

OBDII.pro: P1389 Ford definition
live reference page (obdii.pro)
Supports: Ford-family meaning for P1389: Glow Plug Circuit High Side Low Input
Fetched directly. obdii.pro is a publisher independent of the engine-codes family.

Last updated 2026-09-06.

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