coolant temp sensor

[Phil Rose <pjrose@servtech.com>]

The ACC diagnostic channel 01 ('89 100) has always produced an 09 code,
which I have ignored until recently. According to the Bentley, the 09 code
means a faulty "engine coolant sensor"--the one that's inserted just upside
the large coolant hose/thermostat flange. I ran the electrical tests and
everything appears as per specs--both the sensor resistances and the
voltages at the connector pins. So...why does the ACC tell me there's a
problem here?

According to the manual, the symptom of a defective coolant sensor will be
hard cold-starts and rough running during warmup. I've never noted the
former, but the latter symptom is sometimes present in winter. Is it
possible that the 09 code from ACC channel 1 of '89s is not meaningful?

Phil

Phil Rose		Rochester, NY
'89 100
'91 200q		pjrose@servtech.com