P1390 Ford Code - Octane Adjust Out of Self-Test Range
Quick Answer
The Octane Adjust (OCT ADJ) shorting bar is used to retard spark timing. Common causes include Damage or missing Octane Adjust (OCT ADJ) cap. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- P1390 Ford indicates Octane Adjust Out of Self-Test Range.
- Common causes
- Common causes include Damage or missing Octane Adjust (OCT ADJ) cap.
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code P1390 Ford Description
The purpose of the OCT ADJ self-test is to check the state of the OCT ADJ shorting bar. A Diagnostic Trouble Code (DTC) will be present if the shorting bar is removed or if there is an open circuit. The OCT ADJ shorting bar is similar in shape to the SPOUT in-line connector. On some applications the Power Steering Pressure (PSP) circuit will also have a similar shorting bar connector. DO NOT remove the shorting bar unless directed by a Technical Service Bulletin (TSB).
If you don't have the bar, your timing has been retarded.
What are the Possible Causes of the DTC P1390 Ford?
- Damage or missing Octane Adjust (OCT ADJ) cap
How to Fix the DTC P1390 Ford?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the P1390 Ford code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
Need more information about the P1390 Ford code?
Need more information on how to fix the P1390 Ford code? Get Access to Factory Service Manuals
Need Help with the Code?
Get the P1390 Ford code diagnosed by a professional: Find a repair shop in your area
Frequently Asked Questions about P1390 Ford Code
1. What are the common symptoms of OBDII code P1390 in a Ford vehicle?
- Common symptoms include engine performance issues such as rough idling, hesitation, and stalling.
2. What does the OBDII code P1390 "Octane Adjust Out of Self-Test Range" mean for a Ford vehicle?
- This code indicates that the octane adjust has fallen out of the self-test range set by the vehicle's computer.
3. What are the possible causes of OBDII code P1390 in a Ford vehicle?
- Possible causes include a faulty octane adjust sensor, issues with the fuel system, or a problem with the engine control module.
4. How can I diagnose OBDII code P1390 in my Ford vehicle?
- Diagnosing this code typically involves checking the octane adjust sensor, inspecting the fuel system components, and scanning the engine control module for any related faults.
5. Can OBDII code P1390 in a Ford vehicle cause any long-term damage if left unrepaired?
- While the code itself may not cause immediate damage, it is important to address the underlying issue to prevent potential engine performance problems in the future.
6. How can I repair OBDII code P1390 in my Ford vehicle?
- Repairing this code may involve replacing the faulty octane adjust sensor, addressing fuel system issues, or reprogramming the engine control module.
7. Is it safe to continue driving with OBDII code P1390 present in a Ford vehicle?
- It is not recommended to drive with this code present, as it can lead to poor engine performance and potential stalling, posing a safety risk.
8. Can a DIY enthusiast fix OBDII code P1390 in a Ford vehicle, or is professional help needed?
- Depending on the underlying cause, some DIY enthusiasts may be able to address this code themselves, but in complex cases or for those less experienced, seeking professional help is advised.
9. Are there any specific Ford models known to be more prone to experiencing OBDII code P1390?
- While this code can potentially occur in various Ford models, certain vehicles with specific engine configurations may be more susceptible to triggering OBDII code P1390.
10. How can I prevent OBDII code P1390 from appearing in my Ford vehicle in the future?
- Regular maintenance, such as timely fuel system inspections and sensor checks, can help prevent issues that may trigger OBDII code P1390 from occurring.
Discuss the causes and fixes for P1390 Ford OBDII Code
-
On a 4.6L V8, this is usually a missing or corroded jumper cap for the octane adjust. Simply purchase new cap (~$6 or create your own jumper), plug in, and done.
Fix Your Car Smarter
Try the New AutoCodes App!
Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.
