I have an '88 325is -- great car with about 200k miles on it. The Check Engine light came on recently and blinked the O2 sensor code (2 blinks). Given the age of the car, I just went to the dealer and got a new one. After installation, I cleared the fault light, but it came on again as soon as the car began to warm up. I have cleared the fault several times, with the same result -- the check engine light comes on -- not immediately, but as the engine warms up. The voltage output of the O2 sensor seems OK, but I get no voltage from the heater wires. I understand this indicates a bad O2 sensor heater relay. Could this be the cause of the Check Engine light? If so, where is the relay?
Thanks for any advice or help.