Nissan DTC 1564: ASCD Switch – Malfunction (Voltage Off)

This article is for Nissan made vehicles only.  This code can have different meanings for different manufacturers (most are related to cruise control).

P1564 is a common code that can occur in Nissans or Infiniti’s.  It indicates that the ECM has detected an issue with the Automatic Speed Control Device (ASCD) More specifically, with the voltage resistance at the switch itself.

ASCD is just Nissan’s overly complicated way of saying cruise control.  It should not be considered a breakdown risk.

You can see the switch.  It’s just your cruise control buttons.  You’ll still need to pull the airbag/steering assembly to test it.


Symptoms

P1564 Check Engine

P1564 does not have many symptoms other than the check engine light being illuminated (probably why you are here), and the cruise control system not working.


Causes + Fix

Nissan P1564 is almost certainly going to be caused by an issue with the ASCD steering switch.  

ASCD Switch (Most Common Fix)

The ASCD switch is the many buttons on your steering wheel that lets you operate the cruise control.  As you push them, different voltage levels are being sent to the ECM.  This tells the cruise control to engage, reduce speed, increase speed or quit.  

When the wrong voltage is detected, the ECM will disable the cruise control and throw P1564.

More than likely, the switch itself will need replaced, but you should do your due diligence by testing the wiring harness going to the steering wheel first.  You’ll need a multimeter to test the switch itself.  Here’s a great video of a gentleman diagnosing P1564.  It ends up being the switch itself in this case.

There are three pain points where the voltage should be tested:

  • Between the spring switch and the ECM
  • Between the ASCD switch and the steering wheel harness (requires removing the airbag assembly, if you don’t know what you’re doing it can activate and pop you).
  • At the ASCD switch itself.  Check the incoming voltage and outgoing voltage.  Check that linked video a few lines up.  It’s very thorough and can help you through this.

ECM (Not Very Likely) 

If everything checks out with the wiring harness and ASCD switch, it could be the ECM that is at fault.  But, it’s so unlikely that you should double check everything first.


P1564 Conclusion

P1564 is usually caused by a bad ASCD switch.  We recommend taking it to a shop if you aren’t comfortable with taking the steering assembly apart. 

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