Check Engine Light - Mazda Protege 02

Forgive me if the post has errors as I’m new to the forum. I’ve got a Mazda Protege 02 around 166k miles. Today the check engine light popped on so I had it read for the error codes this afternoon. Check engine light came on solid before the error codes and is now off.

The error codes listed were:
P0660 - intake manifold tuning valve control circuit/open - bank 1
P0117 - Engine coolant temperature circuit low input
P1569 - VTCS circuit low input
And again P0660 - intake manifold tuning valve control circuit/open - bank 1.

Anyone have any clue what’s going on or if it’s serious?
Some minor research hasn’t helped me understand the severity of the issue. Doesn’t seem to die off or have trouble turning over on startup and although I could say it has had a bit of a rough idle lately it burns oil and was about a quart low at the time. Seems to idle much smoother since I topped it off. Oil was changed out about 4 months ago and the spark plugs were swapped with Bosch iridium’s which were set to the correct spacing before installation. Any input is appreciated, I haven’t heard of this issue so I am not sure what to expect in repairs or severity. Thanks in advance.

Check and clean the connections to the VTCS, there are 2 plugs a green plug and a white plug

From what I can find they get disturbed when changing spark plugs.

Should take care of the P0660 and P1569

Might also want to check the connector on the engine coolant sensor.

Thanks for the reply. I’ll give it a shot, if that’s all it ends up being that’ll be an easy fix. Didn’t want to start trying to disassemble the VCTS for cleaning as I don’t have a garage at my current place.

Any idea why the P0117 code tripped? If the connectors were acting up and the VCTS delay valve wasn’t closing correctly I’m assuming that increases air intake and spiked the temp leading to that error code? Not sure if that correct though.

Edit: VTCS not VCTS.

Could be the sensor is faulty, but more likely there’s a loose connection. I’m presuming this code refers to the sensor used by the computer to calculate the needed air/fuel ratios. Those sensors are usually just simple thermistors and not common failure items. If you own a dvm, check the resistance of the sensor. I’m not familiar w/Mazda’s, but on my Corolla I think that sensor measures around 1k - 2 K ohm at room temperature. Worth checking b/c If the computer doesn’t know the correct coolant temperature the engine won’t run as perfectly as it should. And the fuel economy will suffer. On my Corolla if that sensor is disconnected it will turn the CEL immediately.

I went ahead and checked the connections to the VTCS, engine coolant sensor and they seemed pretty clean. I made sure they were tight when plugging them back in. For now the check engine light is off and hasn’t flipped back on yet. Engine sounds pretty good when idle. Might just have to wait with fingers crossed and see if that did the trick over the next couple weeks. I’m guessing it’ll probably show up again in which case I’ll start troubleshooting for faulty wiring/connections. Hoping I’m wrong.


Check engine light is off, did you clear out the codes?

looks like you did a good job of cleaning/ checking connections. I would now clear out the codes and go for a test drive and see if any came back.