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Discussion Starter #1 (Edited)
Our 209 5 has been sitting around due to COVID started showing a check engine light.
Scanning showed two errors both related to the engine air flow.
Opening the hood found 4-8 pretty big sticks in the compartment looked like needed to be a squirrel trying to build a nest or something. Taking a look at the MAF I discovered something had chewed through all of the wires and throught the flex tubing between the MAF and intake.

I used latex caulking to patch the hole in the tubing and set to work repairing the wiring.
What I noticed was the left two wires on the MAF sensor (looking from bumper toward back of car were both black with a pink stripe. I tested these with a meter and found they seem shorted. I did my best to make sure each was repaired to the matching other end, but in all honesty they may be reversed (not likely but possible)

I did didn't check with Denso yet about the sensor wiring, but I expect going from left to right the wires are:
AirFlowSensor+AirFlowSensor-AFSensor outputTempSensor+TempSensor-


If this is correct the two black wires with pink stripe should not be shorted unless there's a diode at the other end of the cabling.

I did clean the sensor, reinstalled everything, cleared the errors, and tested the car out. Performance seemed good, no more sluggishness, AFS readings matched throttle so I was happy. A couple weeks later car is sluggish again, and check engine light came back. Another P101 error.

My son and I disconnected the sensor and I tested the left tow pins from the harness end and found they are still shorted. I didn't test voltage, but that's next just a little difficult as need to go through the wire seals on the connector. My son drove the car yesterday and said the warning light went away, and I didn't clear the error. Could it be working again?

I may just get a new MAF sensor and wiring harness but would like some help with the wiring before hooking anything up. Are my wire descriptions above right? Thanks!
 

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Discussion Starter #2 (Edited)
Just did some checks, and discovered the following:

my proposed wiring shows the following with my labels:


AirFlowSensor-Battery +Battery -
AirFlowSensor+12Vsmall mV12V
AirFlowSensor-12Vsmall mV
AirFlowSens Output~1.8V idle
2.5-2.8 @ 3K RPM

I was a bit confused by AFS+ and AFS- still being driven for a while after key removed, but think that's normal.

Test drive showed no check engine light, so I cleared the error. The car was very responsive to acceleration (although the transmission lagged). Will check trans fluid in the morning.
 
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