P0685: ECM/PCM Power Relay Control Circuit/Open
What Does P0685 Mean?
P0685 is a diagnostic trouble code indicating: ECM/PCM Power Relay Control Circuit/Open. This code relates to the computer and output circuits system. It has been reported in NHTSA complaints across 2 different vehicle models.
Symptoms of P0685
- ⚠️ Check engine light illuminated
- ⚠️ ABS warning light on
Common Causes
- 🔍 Throttle body or throttle position sensor issue
- 🔍 Sensor or control module malfunction
P0685 Reports by Year
Real Owner Reports
From NHTSA complaint database — actual owner descriptions.
"FIRST OF ALL I'M REALLY SURPRISED TO FIND OUT THAT HONDA DOES NOT HAVE A RECALL FOR THE A PCM - ECM POWER RELAY. THIS SHOULD BE A SAFETY ISSUE. BASICALLY WHILE DRIVING MY CAR IF I HAVE THE HEAT ON THE VEHICLE WILL TURN OFF WHEN I SLOW DOWN OR COME TO A STOP. IF I FLASH MY HIGH BEAMS THE CAR WOULD"
— Honda Accord owner, 11/19/2020
"CHECK ENGINE LIGHT WENT ON AND OFF A FEW TIMES, TOOK IT TO AUTOCHECK AND FOUND A CODE. TOOK IT TO DEALER, THEY COULD NOT LOCATE THE CODE AND CLAIMED THERE IS NO ISSUE THEY CAN FIND, COME BACK WHEN IT HAPPENS AGAIN. FEW WEEKS LATER, THE CHECK ENGINE LIGHT CAME AGAIN IN THE EVENING, AND NOW WITH OTHER"
— Honda Accord owner, 02/25/2013
"RE: 2005 FORD ESCAPE HYBRID DEFECT IN THROTTLE BODY ELECTRONIC THROTTLE BODY MALFUNCTION NHTSA ACTION NUMBER: DP12006 OPENED 10/2/2012 DEAR NHTSA, AROUND 4 MONTHS AGO, WE PURCHASED A USED 2005 FORD ESCAPE HYBRID IN NORTH CAROLINA. WE HAVE HAD NUMEROUS ISSUES WITH THIS AND OUR OTHER"
— Ford Escape owner, 08/22/2016
Source: NHTSA Complaints Database
Most Reported Vehicles for P0685
Based on NHTSA owner complaint data.
| # | Vehicle | Reports |
|---|---|---|
| 1 | FORD ESCAPE | |
| 2 | HONDA ACCORD |
P0685 Reports by Vehicle
Detailed NHTSA complaint analysis for each vehicle model.
Frequently Asked Questions
Does this mean my car's computer is bad?
How much does an ECM replacement cost?
What To Do Next
Possible Fixes
- 🔧 Have the code scanned with a professional-grade scanner to read freeze frame data
- 🔧 Test the relevant sensor(s) with a multimeter before replacing
- 🔧 If DIY repair isn't feasible, get a diagnostic from a trusted mechanic ($50-150)
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1
Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
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2
Check for recalls
Go to nhtsa.gov/recalls and enter your VIN. Free repairs if covered.
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3
Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.