P0685 on Nissan: How to Diagnose & Fix
ECM/PCM Power Relay Control Circuit/Open
2 Nissan models · 2 documented issues · 2 critical
P0685 on Nissan by model: symptoms, diagnosis and fix
Nissan recall campaign 10V-517/PC068 covers 2005-2006 Xterra. Oxidation on ECM-relay electrical contacts in the IPDM can interrupt ECM power, cause engine-performance problems and permit stalling at low engine speed. The campaign replaces the relay with a new one after VIN eligibility is confirmed.
Common Symptoms
- Engine stalls at low engine speed
- Engine performance problems
How to Fix
Check Service COMM or Nissan recall status by VIN. If PC068 is open, have a Nissan dealer replace the ECM relay in the IPDM using the campaign procedure at no charge. For a completed or ineligible vehicle with a stall, preserve power-loss data and test ECM power, relay control, IPDM terminals, battery and grounds before replacement. Check the campaign status and confirm the electrical diagnosis before buying a relay or IPDM.
Call to confirm they can assess your vehicle and perform the stated work. Search results do not confirm qualification, eligibility or coverage.
Sources for this issue (2)
Nissan's 10V517000 recall reaches the 2005 and 2006 Frontier pickup. At issue is the ECM relay contained in the Frontier's Intelligent Power Distribution Module assembly. The relay's diode uses a silicon molding to reduce electrical current noise, but Nissan found the relay may allow silicon vapor to form; as silicon evaporates from that molding, arcing deposits silicon oxide on the relay contact. According to Nissan, this can cause the engine to stall — the reason the campaign was filed as a safety recall rather than a service bulletin. Note that the 747,480 units listed apply to the campaign as a whole, which spans several Nissan and Infiniti models.
Common Symptoms
- Engine stalling
How to Fix
Take the truck to a Nissan dealer, where the ECM relay inside the IPDM assembly is replaced free of charge. The recall began December 6, 2010. Before scheduling, enter your Frontier's VIN at nhtsa.gov/recalls — that will tell you whether the relay replacement is still outstanding on your specific truck. Nissan customer service: 1-800-647-7261.
Call to confirm they can assess your vehicle and perform the stated work. Search results do not confirm qualification, eligibility or coverage.
Sources for this issue (1)
P0685 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does P0685 mean on a Nissan?
P0685 stands for "ECM/PCM Power Relay Control Circuit/Open." An open or general fault in the control circuit for the ECM/PCM main power relay. The module cannot properly control the relay that supplies its own switched power. On Nissan it is documented across 2 models: Xterra, Frontier.
What are the most common causes of P0685?
The most common causes of P0685 are: Faulty ECM/PCM power relay, Open in the relay control circuit, Corroded/damaged connectors, Blown fuse, Internal PCM driver fault. The specific cause varies by vehicle.
How much does it cost to fix P0685 on a Nissan?
Repair costs vary widely with the root cause and Nissan model; each issue on this page carries its own estimate where one is published.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.