P0116

The patient is a 1998 4Runner with a 3.4. Check engine light is on. The code is P0116 – Engine coolant temperature (ECT) sensor range/performance problem.

Is there a common failure here? I have a limited amount of time to work on this truck before my son takes it back to school.

Thanks

 

I think the thermostat is stuck open. Is that the way they typically fail? Open? I drove it around for a while and the hottest it got was 167.

Is that something that will cause this fault code?

 

yes. the PCM expects the engine coolant temperature to reach a certain temp by a certain time after initial cold start up. When you replace the thermostat install the new one with the jiggle valve at the 6 o'clock position, not 12 o'clock like on other engines.

 

This same truck just threw the same code. Back in September, I replaced the thermostat with a NAPA part. Sunday I replaced the thermostat again, this time with a shiny Toyota one. The code came back within a day.

Engine Coolant Temperature sensor? What do y'all think?

 

assuming you have an OBDII scan tool that shows live data... if so, see what it shows to verify, I hate throwing parts to solve a problem... if the part is $20ish and easy to get to then I would put it in.

 

I can do that. The real problem is I can only have access to this truck for a very short period of time. My son has it at school and has to bring it home for me to work on, then he has to go back. So, I don't have time for a diagnostic/parts search cycle. Making it worse is I have to have it fixed in the next three weeks or I can't renew the tag.

What else could cause this code?

 

most states that require emissions testing have extensions/exemptions... depending. Here are Georgia's http://www.cleanairforce.com/motorists/frequently-asked-questions/

The sensor is between $30ish and $60ish depending on if aftermarket or factory. It isnt too difficult to replace if you have some basic hand tools. A deep socket is a must.