3 replies to this topic

[garbergtsi]

I have a vehicle im working on, 1996 Volvo 850 non turbo Motronic 4.3, that will not go into closed loop.
Vehicle came in after being at dealer for diagnosis....came in with codes P0131/P0137 (front and rear o2 sensor signal codes). Has 2 new sensors. Codes were cleared and adaptation reset, front sensor hangs out around .6v, as does the rear. The sensor will respond with propane. It will go up to .7 or so when snap-throttled. The readings are the same at the sensor and through the scantool.
Even after hard driving, the sensor will stay around the same area and never flucuate.
Coolant temp is 200+
O2 sensors are being heated
Fuel trims stay at 0, always.
Throttle position is normal
Alt. output is ok and no excessive A/C ripple
No exhaust leaks or secondary air valve
Maf #'s look ok.
Runs great, no driveability complaints.
No codes have came back since clearing, current or pending.

Anybody have any other ideas or possible other sensor that could be restricting closed loop operation??

[Cal3thousand]

I have a vehicle im working on, 1996 Volvo 850 non turbo Motronic 4.3, that will not go into closed loop.
Vehicle came in after being at dealer for diagnosis....came in with codes P0131/P0137 (front and rear o2 sensor signal codes). Has 2 new sensors. Codes were cleared and adaptation reset, front sensor hangs out around .6v, as does the rear. The sensor will respond with propane. It will go up to .7 or so when snap-throttled. The readings are the same at the sensor and through the scantool.
Even after hard driving, the sensor will stay around the same area and never flucuate.
Coolant temp is 200+
O2 sensors are being heated
Fuel trims stay at 0, always.
Throttle position is normal
Alt. output is ok and no excessive A/C ripple
No exhaust leaks or secondary air valve
Maf #'s look ok.
Runs great, no driveability complaints.
No codes have came back since clearing, current or pending.

Anybody have any other ideas or possible other sensor that could be restricting closed loop operation??

Coolant temp of 200+?

is that right?

And the sensors should fluctuate. That doesn't sound right to me that they (at least the front) is not fluctuating at all. What kind of O2 sensor did you use?

[MrWinkey]

Closed loop or the monitor won't go ready?
Just verifying?

[garbergtsi]

new OE volvo sensors...
the sensors respond great to propane and a vacuum leak.
not worried about monitors...i know all about that mess, but it will never go into closed loop and set those 2 codes in about 30 mins of driving

200 is fine with volvo's, their thermostats are set to start opening at 195 and fully open at 210 or so