1994 VX LAF Heater Voltage

[jlane]

I was checking my LAF heater voltage.
I disconnected the LAF sensor.
I used a voltmeter to check the volatge between the yellow/black and black wires in the connector coming from the car.
My manual says it should have battery voltage with the ignition key in the on position.
I only have 6.2v
The black ground wire tested fine. If I connect the red lead of the voltmeter to the positive side of the battery, I can get 12 volts with the black lead still in the connector, connected to the black ground. G101 on the thermostat housing is also fine.

I'm wondering if the manual is written wrong since the power for the LAF heater is coming from the ECU pin A6. I don't see how the voltage could be stepped up. The manual references apprx 7 volts if you test the yellow/black to chassis ground, then battery voltage if you switch to yellow/black and black on the connector. I really don't understand how the voltage would change??????

Could someone please check the voltage between the yellow/black and black wires for the LAF heater on a D15Z1?

Thanks,
jlane

[jlane]

Originally Posted by jlane

I was checking my LAF heater voltage.
I disconnected the LAF sensor.
I used a voltmeter to check the volatge between the yellow/black and black wires in the connector coming from the car.
My manual says it should have battery voltage with the ignition key in the on position.
I only have 6.2v
The black ground wire tested fine. If I connect the red lead of the voltmeter to the positive side of the battery, I can get 12 volts with the black lead still in the connector, connected to the black ground. G101 on the thermostat housing is also fine.

I'm wondering if the manual is written wrong since the power for the LAF heater is coming from the ECU pin A6. I don't see how the voltage could be stepped up. The manual references apprx 7 volts if you test the yellow/black to chassis ground, then battery voltage if you switch to yellow/black and black on the connector. I really don't understand how the voltage would change??????

Could someone please check the voltage between the yellow/black and black wires for the LAF heater on a D15Z1?

Thanks,
jlane

......

[kamesama980]

What you're describing is kind of hard to follow without the manual to compare to but it sounds like you've got excessive resistance on the +12v wire to the heater. I don't know for sure about the difference in voltage to ground but the way honda wired widebands, anythings possible. I'd tend to go with the manual unless I had a good reason to diverge.

[Coconut Sunrise]

Just Checked my 92 VX

7.28 Volts....Across the Yellow & Black
7.28 Volts ...Across the Yellow & Ground
00000 Volts Across the Black & Ground

Coconut