Narrowband Simulation - o2 sensor heater circuit

[belize1334]

Searching has yielded mixed results...

When wiring a wideband to provide narrowband simulation, is it necessary to put a resistor on the original heater-circuit to prevent error codes or will the ECU ignore the no-load condition after the OEM sensor is removed?

 

[Andy_S]

What car are we talking about? Also, resistors on the heater circuit would get extremely hot.

 

[belize1334]

This is for my GVR4. And I'm aware that they'd get hot which is why I'd like to avoid it. But apparently some cars will throw a code if you leave the circuit open...

 

no

 

[belize1334]

Want to expound on that?

 

There is no feedback in the ecu to check that it is heating the o2 sensor. the only error checking it does is on the input signal.
heres the code that sets the o2 sensor failure code

; Timer is expired and the o2 sensor condition is not
; already determined. Since we have been running lean
; for over 30sec, we know the sensor is bad...
;
; Set the flag indicating the o2 sensor conditions was
; determined, and increment o2BadCnt (with max of 255) to
; indicate we have an error condition
; Note that o2BadCnt increase by 1 max every time
; the ECU is turned on (which resets validFlags.1)
;------------------------------------------------------
orm validFlags, #$02 ; Set flag indicating o2 sensor condition was checked (bad in this case)
inc o2BadCnt ; o2BadCnt = o2BadCnt + 1
bne L1468 ; Branch to continue if o2BadCnt != 0
dec o2BadCnt ; o2BadCnt equals 0, go back to 255
bra L1468 ; branch to continue

;---------------------------------------------------------------------------
; if o2BadCnt >= 1, set o2 fault code in current and stored fault variables
;---------------------------------------------------------------------------
ldaa o2BadCnt ;
cmpa #$01 ;
bcs L1469 ; Branch to no o2 fault if o2BadCnt=0
orm faultHi, #$01 ; set oxygen sensor fault code?
orm stFaultHi, #$01 ;
bra L1470 ;

 

[belize1334]

Awesome info... thanks.