Nissan Repair Questions? Ask a Mechanic for Answers ASAP
Hi There, I'm Clayso a certified master automobile technician with 30 years of automotive repair and diagnostic experience.
The DTC P1229 is for a shorted 5 volt reference circuit. The 5v reference can be pulled down by the TPS, APS, MAF, power steering pressure sensor, refrigerant pressure sensor, and the EVAP pressure sensor. Disconnect these one at a time and see when the 5v reference returns. Visually check the wiring around these component connectors.The Red wire is the 5 volt reference to these sensors. Terminal 90 at the ECM does go directly to a potentiometer in the APS sensor that connects directly back to the ECM. I've seen A/C and EVAP pressure sensors cause the same problems.
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The transfer of information between the TPS, APS, MAF, power steering pressure, refrigerant pressure, and the EVAP pressure sensors all takes place within the ECM. As I said earlier disconnecting each of these components one at a time until the 5v reference returns will reviel any sensor shouted and pulling down the reference.
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What did you find and what did you do?
Hey there, new expert here.
The problems your experiencing now are likely a result of the a/c auto amp. Do you ever put change on the shelf in front of the center display?
The a/c auto amp controls the combination meter and hvac controls
You need to replace it, if it has a coin in it as it shorts out some of the circuits by bridging and grounding them.