P0343 on a 2012 Jeep Grand Cherokee
Cam Position Sensor High Input (Bank 1)
P0343 on a 2012 Jeep Grand Cherokee indicates cam position sensor high input (bank 1). It usually stays drivable short-term but should be diagnosed promptly. The most common cause is open circuit in the cam sensor signal wire or its ground (typically $80–$350). Confirm the root cause before replacing parts.
What does P0343 mean on a 2012 Jeep Grand Cherokee?
P0343 is set when the ECM sees the Bank 1 "A" camshaft position sensor circuit sitting above its calibrated maximum voltage. On most engines "A" is the intake camshaft, or the single cam sensor on engines with only one. Because a Hall-effect cam sensor normally idles near reference voltage and pulls the line low as each reluctor tooth passes, a circuit stuck high usually means the sensor is not pulling at all: an open signal or ground circuit, a short to a power source, or a dead sensor. P0343 is the mirror image of P0342.
The symptoms, causes, and diagnostic steps below describe P0343 itself, so they read the same on nearby Jeep Grand Cherokee model years. Powertrain and trim details vary year to year — confirm the specifics against your own vehicle before buying parts.
Is it safe to drive a 2012 Jeep Grand Cherokee with P0343?
In most cases a 2012 Jeep Grand Cherokee stays drivable for short trips with P0343 active, but diagnose and repair it promptly. This is a high-severity code — ignoring it can lead to further damage or a failed emissions test.
What are the symptoms of P0343 on a 2012 Jeep Grand Cherokee?
- Check Engine Light is illuminated
- Hard start with extended cranking
- Possible complete no-start condition
- Stalling, sometimes intermittent
- Rough running and reduced power
- Hesitation under acceleration
- Reduced fuel economy
What causes P0343 on a 2012 Jeep Grand Cherokee?
| Cause | Likelihood | Estimated repair (USD) |
|---|---|---|
| Open circuit in the cam sensor signal wire or its ground | Most common | $80–$350 |
| Failed camshaft position sensor (output stuck high) | Most common | $100–$400 |
| Cam sensor signal wire shorted to a power source | Common | $80–$350 |
| Corroded connector adding resistance to the signal or ground path | Common | $50–$250 |
| Loose or incorrectly torqued sensor leaving the air gap too large Costs nothing to check — a sensor backed out of its bore reads high because it never sees the reluctor. | Occasional | $20–$100 |
| Damaged or missing teeth on the camshaft reluctor / tone wheel | Occasional | $300–$1,200 |
| Failed PCM input for the cam sensor circuit | Rare | $400–$1,500 |
Cost ranges are editorial estimates for parts and labor at an independent U.S. shop — not quotes. What you actually pay moves with your region, the shop's hourly rate, which engine you have, and how much diagnostic time the job takes. Dealer service departments typically sit above these ranges.
How to diagnose this on a 2012 Jeep Grand Cherokee
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Confirm the sensor is seated and torqued
Before any electrical testing, check that the sensor is fully seated in its bore and its bolt is tight. A sensor backed out even a few millimetres — by a loose bolt, a missing spacer, or a previous repair — sits too far from the reluctor to trigger and reports a permanently high circuit. This is a five-minute check that occasionally ends the whole diagnosis.
Tools: Socket set, Torque wrench
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Inspect the connector and harness
Unplug the sensor and look for pushed-back or corroded pins, oil intrusion, and chafing where the harness crosses brackets or the valve cover. High-input codes are frequently a poor ground connection, and a green crusty ground pin is the visual signature of one.
Tools: Connector unlock tool, Flashlight, Electrical contact cleaner
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Check the ground circuit resistance
With the connector unplugged, measure resistance from the sensor's ground pin to a known-good chassis ground. It should be very close to zero. Anything more than a couple of ohms is a bad ground, and a bad ground is one of the most common reasons a perfectly good sensor reports high.
Tools: Multimeter, Wiring diagram
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Test the signal circuit for a short to power
Unplug both the sensor and, if you can access it safely, the ECM connector. Measure the signal wire against ground with the key on. Voltage present on a wire that is disconnected at both ends means it is touching a power source somewhere along its run — find and repair the chafe point.
Tools: Multimeter, Wiring diagram
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Scope the signal during cranking
Capture the waveform while cranking. A working sensor produces clean square pulses that swing from reference voltage down toward ground. A flat trace sitting at the top rail confirms the sensor is never switching — either it is dead, or the reluctor is not passing close enough to trigger it.
Tools: Oscilloscope, Back-probe pins
NHTSA complaints & recalls for the 2012 Jeep Grand Cherokee
Owner-reported safety complaints and official recalls filed with the U.S. National Highway Traffic Safety Administration for the 2012 Jeep Grand Cherokee. Use these to gauge how common a problem is on your specific vehicle before you start chasing Jeep Grand Cherokee diagnostics.
- ENGINE 282
- POWER TRAIN 101
- ELECTRICAL SYSTEM 834
- SERVICE BRAKES 305
- FUEL/PROPULSION SYSTEM 215
11 active recalls
- ELECTRICAL SYSTEM Nov 2019
Chrysler (FCA US LLC) is recalling certain 2011-2013 Dodge Durango and Jeep Grand Cherokee vehicles equipped with a 3.6, 5.7, or 6.4 liter engine and previously recalled under NHTSA Recall 14V530 or 15V115. The fuel pump relay inside the Totally Integrated Power Module (TIPM-7)…
NHTSA campaign 19V813000 - ELECTRICAL SYSTEM:ALTERNATOR/GENERATOR/REGULATOR Jul 2017
Chrysler (FCA US LLC) is recalling certain model year 2011-2014 Dodge Challenger, Dodge Charger, Chrysler 300, Dodge Durango, and 2012-2014 Jeep Grand Cherokee vehicles. The affected vehicles have electro-hydraulic power steering (EHPS) and are equipped with a 5.7L or a 3.6L eng…
NHTSA campaign 17V435000 - ENGINE AND ENGINE COOLING:ENGINE:GASOLINE:TURBO/SUPERCHARGER Oct 2017
Accessible Technologies, Inc. (ATI) is recalling certain ProCharger Superchargers, model numbers AB037A-100, AB037A-100P, and A037A-100B, sold for installation on 2012-2017 Jeep Grand Cherokee SRT8 and SRT vehicles. The supercharger mounting bracket may contact and damage the AB…
NHTSA campaign 17E061000 - SERVICE BRAKES Sep 2017
Chrysler (FCA US LLC) is recalling certain 2011-2014 Dodge Durango and Jeep Grand Cherokee vehicles. The affected vehicles had brake booster shields installed under a previous campaign to prevent water from entering the brake booster and limiting braking ability. This recall is…
NHTSA campaign 17V572000
How do I fix P0343 on a 2012 Jeep Grand Cherokee?
- Replace the camshaft position sensor with an OEM part
- Repair the open signal or ground circuit
- Repair a signal wire shorted to power
- Clean or repair the sensor connector and its ground
- Re-seat and correctly torque the cam sensor
Engines in the 2012 Jeep Grand Cherokee
The 2012 Jeep Grand Cherokee was offered with the 3.6L 6-cylinder, 5.7L 8-cylinder and 6.4L 8-cylinder engines. Which one you have changes where P0343 is most likely to originate, so confirm your engine before ordering parts.
Engine data: EPA fueleconomy.gov.
P0343 vs P0342
Same sensor, opposite electrical failures:
- P0342 (low input) — the circuit is being pulled toward ground when it shouldn’t be. Look for a short to ground or a sensor that has failed low.
- P0343 (high input) — the circuit is stuck near reference voltage and never pulls down. Look for an open circuit, a bad ground, or a sensor that is not switching.
Both are voltage-rail faults, which is why both tend to be wiring problems more often than the sensor. The exception is a sensor that has failed internally in a way that leaves the output line unloaded, which looks identical to an open circuit from the ECM’s side.
Check the air gap before you check anything electrical
A cam sensor reads the passing teeth of a reluctor wheel across a small air gap. If that gap is too big, the sensor never triggers, and the ECM sees a circuit that is permanently high — exactly P0343. Causes of a too-large gap are mundane: a loose mounting bolt, a sensor not pushed fully home during a previous job, a missing shim, or debris packed into the bore. Take thirty seconds to confirm the sensor is seated and tight before you start chasing wires.
Why the ground circuit deserves suspicion
Cam sensor grounds often share a splice with several other engine sensors. When that splice corrodes, the sensor cannot pull its signal line down properly, and the circuit reads high. The tell is other seemingly unrelated sensor codes setting alongside P0343 — if you have a scattering of codes that don’t share a system, stop testing sensors and go find the shared ground.
When this becomes a shop job
If the wiring tests clean, the ground is solid, a new OEM sensor is installed, and P0343 still returns, the remaining suspect is the reluctor wheel itself — chipped teeth, a slipped press-fit ring, or debris on the target. Seeing it usually means removing the timing cover, which is where the job stops being a driveway repair on most modern engines.
P0343 on a 2012 Jeep Grand Cherokee: frequently asked questions
What does diagnostic trouble code P0343 mean on a 2012 Jeep Grand Cherokee?
P0343 is set when the ECM sees the Bank 1 "A" camshaft position sensor circuit sitting above its calibrated maximum voltage. On most engines "A" is the intake camshaft, or the single cam sensor on engines with only one. Because a Hall-effect cam sensor normally idles near reference voltage and pulls the line low as each reluctor tooth passes, a circuit stuck high usually means the sensor is not pulling at all: an open signal or ground circuit, a short to a power source, or a dead sensor. P0343 is the mirror image of P0342.
What are the symptoms of P0343 on a 2012 Jeep Grand Cherokee?
Check Engine Light is illuminated. Hard start with extended cranking. Possible complete no-start condition. Stalling, sometimes intermittent. Rough running and reduced power. Hesitation under acceleration. Reduced fuel economy
What causes P0343 on a 2012 Jeep Grand Cherokee?
Open circuit in the cam sensor signal wire or its ground (most-common). Failed camshaft position sensor (output stuck high) (most-common). Cam sensor signal wire shorted to a power source (common). Corroded connector adding resistance to the signal or ground path (common). Loose or incorrectly torqued sensor leaving the air gap too large (occasional). Damaged or missing teeth on the camshaft reluctor / tone wheel (occasional). Failed PCM input for the cam sensor circuit (rare)
Is it safe to drive a 2012 Jeep Grand Cherokee with P0343?
In most cases a 2012 Jeep Grand Cherokee stays drivable for short trips with P0343 active, but it should be diagnosed and repaired promptly — this is a high-severity code. Ignoring it can lead to further damage or a failed emissions test.