Test Dc: Step 10: Notes

10) Code 66: Check Continuity of MAF Signal & VPWR Circuits  Code 66 indicates that MAF signal was less than .40 volt during engine continuous operation or during KOER Self-Test. Possible causes for this fault are:

• Open MAF circuit
• Open VPWR circuit to MAF sensor
• Open PWR GND circuit to MAF sensor
• MAF circuit shorted to ground
• Faulty ECA or MAF sensor
• Air leak before or after MAF sensor
• MAF sensor disconnected

Ensure key is off. Disconnect and inspect 60-pin connector at ECA. Repair and service as necessary. Disconnect the MAF sensor and install breakout box, leaving ECA disconnected. Set DVOM on 200-ohm scale. Measure resistance between VPWR circuit at the MAF sensor vehicle harness connector and test pins No. 37 and 57 at the breakout box.