Haltech Wideband 02 Controller Manual - Manual (Page 14)

8.7 Sensor Timing Errors
These errors are typically encountered when the sensor does not have outside air available as
reference gas. If you encounter this error, restart the HWC and operate the sensor in free air. If
you still encounter this error, the sensor may be bad and needs to be replaced.
Replacement sensors are available from your nearest VW dealer under the VW part-number
021-906-262-B or direct from Haltech.
Sensor timing errors are also common when the sensor overheats. Relocate the sensor further
downstream in the exhaust and/or install a heat sink.
Sometimes it’s possible to encounter Error 08 when the exhaust gas suddenly gets too rich.
Normally the HWC will display a ‘too rich’ indication if the exhaust gas is too rich. If the mixture
gets rich very suddenly, the HWC cannot distinguish between a too rich condition and a sensor
timing error.
8.8 Calibration tricks and hints
If the outside air-pressure changes dramatically (for example from sea-level to 10 000 ft) the
sensor calibration will be off. Recalibrate the HWC at the new altitude and then tune your engine
to the same AFR as on sea level. This insures the same AFR as determined at the different
altitude is used by the engine to maximize performance.
Note: The following tricks can only be performed on EFI equipped engines, not
carbureted or CIS engines.
Sometimes it is inconvenient to remove the sensor from the exhaust pipe for recalibration. On EFI
equipped vehicles the following trick can be used:
EFI systems usually shut the injectors off during coast-down conditions (throttle closed and RPM
typically greater than 1500 RPM). In this situation the engine just acts as a car-driven air-pump
and fills the exhaust system quickly with pure air. In this situation the sensor can be recalibrated.
If you need to step on the throttle while a calibration is in progress, you MUST repeat the
calibration.
To quickly clear out remaining exhaust gas from the exhaust tract, it also helps to rev the car up
in neutral, then at high RPMs shut the engine off while holding the throttle fully open. While the
engine rotates to a stop it will act as air-pump. Holding the throttle fully open (WOT) minimizes
pumping losses and allows the engine to pump a maximum of air without the need to suck it past
the throttle plate.
8.9 Analog Output tricks/hints
Sometimes there is a ground offset between the device that receives the analog output voltage
and the HWC. This can be specially true if the System ground is not connected to the same
ground as the measurement device using the analog out. Both devices reference different
grounds and therefore see different voltages. So to compensate for the ground offsets the analog
output voltage points have to be shifted by the ground offsets. To measure what the real ground
offset is, you can program the analog outputs temporarily to output a flat line voltage by entering
the same voltage in both fields for the two analog out programming points. This way the analog
output voltage will be fixed, independent of current AFR and can therefore be measured and
compensated for easily
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