DodgeBruhBoy Posted August 10 Report Share Posted August 10 As I was working on my vehicle (Previously had crankshaft/camshaft issues) all of a sudden, I got the following codes: -C0021-02 code which is Brake Booster - General Signal Failure -C121C-00 Torque Request Signal Denied -C212A-16 System Voltage - CIrcuit Voltage Below Threshold -U0401-00 Implausible Data Received from ECM/PCM "A" -C2101-17 Battery Voltage High - Circuit Voltage Above Threshold. (The battery was overcharged, it's tested at 14V, and now we are trying to run it down.) The car is driving and braking smoothly when the ground is level, I can drive forward and reverse with no (braking) issues. But when I drive up the driveway (10%-20% incline, then levels outs) the BRAKE light comes on the dash and then the pedal gets rock hard and it becomes difficult to brake. This happens when I am going forward or reverse into the driveway. How should I approach these? Quote Link to comment Share on other sites More sharing options...
John/Horace Posted August 10 Report Share Posted August 10 Battery is fine, can't overcharge a lead acid battery unless alternator is faulty. You had a high and low codes, could be surge from something else. Your meter may not be perfectly accurate. Start by checking master cylinder brake fluid level in reservoir under hood. If a incline is causing the light to come on it could be low, should be between max and min marks. The light being triggered could cause random codes from abs. As brake pads wear the fluid level goes down; caliper pistons moving out to auto adjust. Quote Link to comment Share on other sites More sharing options...
DodgeBruhBoy Posted August 10 Author Report Share Posted August 10 1 hour ago, John/Horace said: Battery is fine, can't overcharge a lead acid battery unless alternator is faulty. You had a high and low codes, could be surge from something else. Your meter may not be perfectly accurate. Start by checking master cylinder brake fluid level in reservoir under hood. If a incline is causing the light to come on it could be low, should be between max and min marks. The light being triggered could cause random codes from abs. As brake pads wear the fluid level goes down; caliper pistons moving out to auto adjust. Hey John, Thank you for responding. Yes, the brake fluid reservoir was a little under the middle so I filled it up but the issue is still there. I did order new brake pads and rotors and will be installing them this weekend. If the issue continues, what would you look at after? Quote Link to comment Share on other sites More sharing options...
5rebel9 Posted August 10 Report Share Posted August 10 42 minutes ago, DodgeBruhBoy said: Hey John, Thank you for responding. Yes, the brake fluid reservoir was a little under the middle so I filled it up but the issue is still there. I did order new brake pads and rotors and will be installing them this weekend. If the issue continues, what would you look at after? not just an issue of pads and rotors, but that caliper slide pins are "free" and not seized. And also that rear calipers are also in good "order". BTW.....WHAT was the cause/fix to the crank/no start/timing chain issue????? many folks gave their time and suggestions to try and assist you, it would be nice to find out what was going on. 2late4u and Dean H 2 Quote Link to comment Share on other sites More sharing options...
DodgeBruhBoy Posted August 15 Author Report Share Posted August 15 On 8/10/2026 at 4:34 PM, 5rebel9 said: not just an issue of pads and rotors, but that caliper slide pins are "free" and not seized. And also that rear calipers are also in good "order". BTW.....WHAT was the cause/fix to the crank/no start/timing chain issue????? many folks gave their time and suggestions to try and assist you, it would be nice to find out what was going on. Sorry for the delay, I didn't address that entirely because it seems to still be a possible issue. But here is where I am...I went through multiple cam/crank sensors and still did not get it to start. Now we just went all in and replaced the cam/crank sensors with mopar and the crank sounded much healthier (no start) and did kick over a few times. We then went back to basics and followed up with the throttle body and opened it manually by hand and it officially started. It ended up running crazy rough, super aggressive with fluctuations between 500-900 rpms. Here is what through us for a loop, we ran the obd using a snap on OBD tester (most codes were gone) and ended up getting a MAF code so we replaced the sensor and after 30 seconds the engine started and stabilized. After driving around, the codes above came on. We went to autozone to see what codes they get and the original codes showed up as well....twice. P0016 — Crankshaft/Camshaft Position Correlation, Bank 1 Sensor A (Showed up twice) P0017 — Crankshaft/Camshaft Position Correlation, Bank 1 Sensor B (Showed up twice) P0008 — Engine Position System Performance, Bank 1 (Showed up twice) P000B — Exhaust “B” Camshaft Position Slow Response, Bank 1 (Showed up twice) C0021-02 — Brake Booster, General Signal Failure C121C-00 — Torque Request Signal Denied C212A-16 — voltage-below-threshold type fault U0401-00 — Invalid Data Received From ECM/PCM C2101-17 — another voltage-related chassis/ABS fault It now seems because of these voltages codes, we are getting all sorts of other random codes, mind you we had NO Brake issues prior to the cam shaft Crankshaft issues. We also never did the relearn. Any ideas on where to go from here? Quote Link to comment Share on other sites More sharing options...
Dean H Posted August 16 Report Share Posted August 16 Try the the throttle body relearn function. Quote Link to comment Share on other sites More sharing options...
DodgeBruhBoy Posted August 16 Author Report Share Posted August 16 12 hours ago, Dean H said: Try the the throttle body relearn function. Ok, I will go ahead and try that. I still didn't do the Crankshaft/Camshaft relearn, so should I do that first? And then do the Throttle Body relearn? Just want to make sure I approach it correctly: 1. Crankshaft/Camshaft relearn 2. Let car run 1-3 minutes (idle only, then turn off) 3. Throttle body relearn (then start car/idle for 1-3 mins) 4. Scan/delete codes if any. 5. Drive it around for 10-15 to see if any codes come back. Should this be my approach? Quote Link to comment Share on other sites More sharing options...
Dean H Posted August 16 Report Share Posted August 16 Both relearns using a capable scan tool. Quote Link to comment Share on other sites More sharing options...
DodgeBruhBoy Posted Monday at 07:34 PM Author Report Share Posted Monday at 07:34 PM (edited) On 8/16/2026 at 2:18 PM, Dean H said: Both relearns using a capable scan tool. After cleaning the Throttle body, the vehicle would not start, I then did a throttle body reset using the pedals/flicking light method and the vehicle started right up. (A little rougher idle prior to cleaning) but it leveled out after letting it sit and then driving for 20 mins. Even though the vehicle is running and driving, the XTOOL A30D scan tool is not allowing the crankshaft/camshaft and throttle body Relearns to be performed. This is driving me nuts, it also wont let me delete any codes. I'm also getting random ass codes like tire pressure sensor 3 & 4 failure even though its giving me appropriate tire pressure. See attached...The ones circled in green, those sensors or items that have been replaced....(The relearned cant be performed) JCJourney202608171334_260817_143154.pdf Edited Monday at 07:38 PM by DodgeBruhBoy Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.