Subaru Outback Cuts Out

Diagnose and fix Subaru Outback Cuts Out problems

If you have a Subaru Outback Cuts Out issue, check for the symptoms below and scan for trouble codes P0638 or P2101.

Symptoms: Car won’t idle. Car won’t accelerate. The problems may be permanent or intermittent.

P0638 – Throttle actuator control range/performance Bank 1

P2101- Throttle actuator control motor circuit range/performance

Don’t assume you need a new electronic throttle body based on these two throttle actuator trouble codes. In many cases, the problem can be as simple as a bad relay. Here’s how to test.

First, check fuse SBF-7. If it’s good, proceed with these tests.

With the key in the OFF position, remove the electronic throttle control relay located under the passenger side of the dash. See the diagram for terminal numbers. Connect battery positive to relay terminal 5 and negative to relay terminal 6. Then measure resistance across terminals 7 & 8. It should be less than 1 Ω. If it’s greater than 1Ω, replace the relay.

Next, check for power to the electronic throttle control relay socket. Set your DVOM to DC volts. Connect the positive lead to the terminal that was connected to relay terminal 7 and the negative lead to ground. You should see battery voltage. If not, you have an open in the wire from the fuse. Then check for battery voltage in the connector that attached to relay terminal 6, with the negative connected to ground. If no battery voltage, check the main relay.

Shops are finding pitting and corrosion on the electronic throttle control relay contacts and the main relay. They’re inexpensive and easy to replace.

©, 2016 Rick Muscoplat

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