Not sure where to start here. My 06 LT 2.4L with 150k miles began to start slowly and sluggishly a few days ago, taking more cranks then usual. Didn’t get any relevant codes until this morning away from home, p0326 & p0336. On the home my crazy guages have returned after being gone for almost a year. This includes bouncing speedometer, BRAKE indicator , power steering warning, ABS and traction lights, and the car alarm indicator. No hard shifting or weak power though. Any advice on where to start is much appreciated.

Edit: forgot to add that I couldn’t connect to OBD anymore but there was power to the connector. NOW I am able to connect after restarting the car and the codes are endless:

U0121-00
c0561-71
c0550-37
C0000-71
c0845-01
u2100-00
u2107-00

edit 2: the car is running after an extremely slow and sluggish start without crazy gauges, but I’m sure it will come back

 

A few things to check out -

the four 7mm bolts under the cover of the underhood fuse block need to be gorilla tight.

The battery could be discharged or bad.

There could be loose or corroded connections between the battery and the alternator, including broken battery terminal clamps, ground cable to body, connections under the red cover on the side of the underhood fuse block, connections at the large lug of the starter, and at the large lug of the alternator.

Loose or bad, Serpentine Belt and/or tensioner.

 

ALL codes are relevant!. In this case they all put together point to either wires or fuses; the most common is the 4 bolts inside the under hood fuse box are loose; they need to be tightened REALLY tight not just feels tight.

 

Thank you both. My 4 bolts for the fuse box were noticeably loose, those are gorilla tight now. Serpentine belt is good, battery connections are good and alternator.

I replaced the crankshaft position sensor since I was getting p0336, no rpm reading, but 5 volts at the connector.

The car started up sluggishly a few times, then it’s back to making a loud squeaking sound with no cranking, and smoke from starter area, same thing before I replaced the sensor.

I charged the battery overnight and now I’m getting no squeaking sound and no cranking when starting but I can hear the starter solenoid activating. The battery tested “good”



current codes are U0121-00 at both the ECM and TCM. I’m stuck again, should I replace the starter?

edit: After further reading, I believe an oil leak from the oil pressure sensor fried my starter. I’ll look into replacing both

 

I was right, oil pressure sensor leak ruined the starter. I replaced both. my guess is the load from the fried starter made the rest of the electronics freak out and throw codes. Thanks for the tip about the fuse* box bolts and sorry for the jumble of info

edit: fuse box* not battery box

 

It’s running and driving, enjoy the cruising!