VOLVO - 850 - OBD code 1-5-4

[cmdz]

1994 - 850 - non turbo

A shop replaced my radiator last week, and when they gave it back to me, the car started to overheat again after 5 minutes.

I brought it back the next day and they said it was the thermostat. They apologized and replaced that.

The CEL was on and idling rough, but at least the car was not overheating.

Read the OBD code and got code 1-5-4, after clearing it, the car seemed to be okay.

It idled rough occasionally on a hot day last week but then otherwise was fine.
I drove for 100 miles without the CEL coming back on.

Then on Saturday I was trying to determine what steering rack I had, and I jacked up the car, only in the front.
Took a couple pics and lowered it back to the ground.

A couple hours later I went to go to the store and started the car.

It struggled a bit as it pulled away and then instantly the CEL came back on & it started to idle rough like before.

Just checked the ODB and it's Returning the same code: 1-5-4

tldr;

1994 Volvo 850 is giving me code "1-5-4" and is idling rough.

1-5-4 = EGR system – leakage or excessive flow


Any one with experience on this and advice on where I should start first to fix myself?

thank you

[cmdz]

I'm seeing a lot of forums post suggest that when doing the radiator to also do the thermostat and ECT sensor.

Feeling that I should start there.

[RickHaleParker]

EGR = Exhaust Gas Recirculation.