Codes showed P0101 and P1778. I changed the Massive Airflow Sensor for about $130 but it didn't help.

Sent car to Valley Automotive Repair and Electric (425-310-4788) towed by Maple Valley Towing (Jason) 425-433-0516.

Their evaluation fee is $175 to $275.

They said the transmission is bad. The remanufactured transmission plus towing came to about $6200. They are trying to find a used transmission instead, with a total cost closer to $5100 [3/17/2022]

I accepted their suggestion to spend about $100 to do a quick analysis to make sure the rest of the car is OK so that we don't throw this money for the transmission to avoid another unforeseen cost.

[3/17/2022]

Approximately September 2024.

Loud clanking Sounds like deiseling/exagerated camshaft-to-lifter clicking.

Robert reported that he drove his car at 130 Mph, then he heard a loud noise and then the car would hardly move.

Replaced timing chain because the clicking/clanging seemed to be coming from exactly where the upper camshaft gears were located. Reassembled car, clanging still there.

Examined valves with small camera, looks like one of pistons lightly struck valves by seeing light impression on piston, and carbon missing from valve. Took engine apart even removing head. Could not see any problems. Months go by.

Hired George to help reassemble car. He took engine out of car. Didn't replace much because most parts seemed OK.

Still working on Robert's car to prevent the loud clanking.

I applied 12V, then 14V directly to Variable Valve Timing VVT Solenoid. This caused the clanking to approximately be reduced to half. Clanking comes back when voltage is removed.

Took VVT Solenoid out of car, measured resistance to be about 8 Ohms, which is as expected. Applied voltage, and the switch action seems OK, if on the mellow side. Power supply sent about 1.5 amps at about 12.3 V, which agrees with the approximate 8 Ohms of resistance.

Measured Pink/Purple lines at the VVT Solenoid with car on, engine not running, and it measures about 12.3V. Seems about right, but it doesn't explain why the clanking reduces when connecting about 12.3V from my power supply directly to the Solenoid. The wiring may have some resistance, but didn't measure for this.

Ordered a replacement VVT Solenoid (delivery scheduled 8/31/2025) from Amazon for about $18.

Wiring Diagrams for 2012 Nissan Altima

Installed VVVT Solenoid. Possibly some changes, but the clanging remains. It might even be not quite as good as the original solenoid when applying 12V or 14V. [8/31/2025]

Right now, thinking that the VVT camshaft gear is the cause, but don't have proof of this.

[9/1/2025]