O2 heater cycle won't run

Mikee024 said:
I believe he wants you to test it right after startup and then again about 15 minutes later (once the engine compartment has warmed up).
Click to expand...

test results:

key on, engine off: 12ish
engine on, before closed loop: just above 14ish
engine on, in closed loop: just below 14ish
 
imactj2004 said:
test results:

key on, engine off: 12ish
engine on, before closed loop: just above 14ish
engine on, in closed loop: just below 14ish
Click to expand...

Interesting... Once the engine has run for 15 mins or so.... there should have been a lowering of the charging voltage coming from the alternator....
The BTS sends a signal to the ECU, the ECU controls the charge rate of the alternator to the battery and supplies the vehicles electronic components trying to maintain a preset system voltage.
When the battery is cold the alternator charges at a higher rate and as the battery warms up the charge rate slowly drops to the preset factory voltage.
IF there is a problem with the BTS or if the sensor is disconnected; that would affect the alternator charge rate depending upon the factories default set point.
IF you feel comfortable... measure the voltage at the alternator charging stud while testing to see if there is a difference then at the battery.
 
CharlesHS said:
Interesting... Once the engine has run for 15 mins or so.... there should have been a lowering of the charging voltage coming from the alternator....
The BTS sends a signal to the ECU, the ECU controls the charge rate of the alternator to the battery and supplies the vehicles electronic components trying to maintain a preset system voltage.
When the battery is cold the alternator charges at a higher rate and as the battery warms up the charge rate slowly drops to the preset factory voltage.
IF there is a problem with the BTS or if the sensor is disconnected; that would affect the alternator charge rate depending upon the factories default set point.
IF you feel comfortable... measure the voltage at the alternator charging stud while testing to see if there is a difference then at the battery.
Click to expand...

Hmmm…mind expanding on what to expect when measuring at the stud? And, if I dont get expected results, what would next steps be for troubleshooting/diagnosis?
 
here’s another bit of information which I havent mentioned. The EVAP monitor also will not set.

again: I dont get any codes or CEL but these two monitors continue to say “not ready” despite thousands of miles of drive cycle tests.
 
Update: finally gave in and brought it to Dealer. Turns out that the ECT sensor was faulty which was prohibiting the HTR Monitor to set.

Annoyed that I didn't get an actual DTC that indicated that there was a faulty ECT, but relieve to have this finally fixed.
 
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imactj2004 said:
Update: finally gave in and brought it to Dealer. Turns out that the ECT sensor was faulty which was prohibiting the HTR Monitor to set.

Annoyed that I didn't get an actual DTC that indicated that there was a faulty ECT, but relieve to have this finally fixed.
Click to expand...

Glad you got it solved man that’s the most important part! And good to know for the rest of us who didn’t have the engine temp sensor on our radar.
 
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