Failed camshaft position sensor. Sensor wiring open or shorted. Poor electrical connections, such as a corroded connector or bent pins. Bad or weak battery (listed by OBD-Codes.com, which says a low battery can set this code). Faulty starter or poor wiring to the starter (listed by OBD-Codes.com). Broken tone ring (reluctor wheel), the toothed ring the sensor reads (listed by RepairPal). Engine computer (PCM) failure, which is less likely (listed by RepairPal).

Charge or replace a weak battery. Repair starter wiring or replace a weak starter if testing shows excessive draw. Repair open or shorted wiring, or clean and repair a corroded connector. Replace the camshaft position sensor (RepairPal's most common repair for this code, and OBD-Codes.com's final step). Repair a broken tone ring if inspection finds one. Diagnose and replace the PCM only after the sensor, wiring, battery and starter check out.

P0342🔧 Engine management / camshaft position sensorStop and fix promptly

P0342: Camshaft Position Sensor A Circuit Low, Bank 1 (Meaning, Causes, Fixes)

Q: What does P0342 mean?

P0342 means the engine computer sees a signal from camshaft position sensor A on bank 1 (the side with cylinder 1) that is too low or weak to read reliably. Expect a check engine light and possibly lack of power, stalling or hard starting. Causes include a failed cam sensor, open or shorted wiring, poor connections, a weak battery or starter, a broken tone ring, or less often the engine computer. The camshaft position sensor (CMP) reports the exact rotational position of the camshaft. RepairPal explains that the engine computer (PCM) uses this signal to control the fuel injectors and ignition coils. OBD-Codes.com describes how it works with the crankshaft position sensor: the crank sensor tells the PCM where the pistons are, and the cam sensor tells it the position of the intake camshaft lobe relative to that, so the PCM can time fuel injection for each cylinder. OBD-Codes.com defines P0342 as a generic code meaning sensor A's signal on bank 1 is too low, or not strong enough, so it's vague and hard to interpret. Bank 1 is the side of the engine that contains cylinder 1. OBD-Codes.com notes that on GM vehicles the description is slightly different: 'CMP Sensor Circuit Low Input Conditions'. Note where the sources differ: RepairPal's title doesn't mention a bank, and its explanation (the PCM sets the code on an irregular signal or no signal) is the same wording it uses for other camshaft sensor codes such as P0345 and P0346. The two sources' cause lists also differ: OBD-Codes.com includes a faulty starter, poor starter wiring and a bad battery, while RepairPal includes a broken tone ring and PCM failure. The bank 2 version of this code is P0347. Related codes are P0340 (circuit), P0341 (range/performance), P0343 (circuit high) and P0344 (intermittent).

Q: Can I keep driving with P0342?

Stop and fix promptly. Get this diagnosed promptly. RepairPal rates P0342 'Urgent' and lists an engine that may not start among the symptoms, and OBD-Codes.com lists lack of power, stalling and hard starting. If the engine stalls, loses power or is hard to start, avoid relying on the car in traffic or on the highway until it's checked.

Reviewed 2026-10-24 · Based on 2 cited source(s)

What P0342 means

The camshaft position sensor (CMP) reports the exact rotational position of the camshaft. RepairPal explains that the engine computer (PCM) uses this signal to control the fuel injectors and ignition coils. OBD-Codes.com describes how it works with the crankshaft position sensor: the crank sensor tells the PCM where the pistons are, and the cam sensor tells it the position of the intake camshaft lobe relative to that, so the PCM can time fuel injection for each cylinder. OBD-Codes.com defines P0342 as a generic code meaning sensor A's signal on bank 1 is too low, or not strong enough, so it's vague and hard to interpret. Bank 1 is the side of the engine that contains cylinder 1. OBD-Codes.com notes that on GM vehicles the description is slightly different: 'CMP Sensor Circuit Low Input Conditions'. Note where the sources differ: RepairPal's title doesn't mention a bank, and its explanation (the PCM sets the code on an irregular signal or no signal) is the same wording it uses for other camshaft sensor codes such as P0345 and P0346. The two sources' cause lists also differ: OBD-Codes.com includes a faulty starter, poor starter wiring and a bad battery, while RepairPal includes a broken tone ring and PCM failure. The bank 2 version of this code is P0347. Related codes are P0340 (circuit), P0341 (range/performance), P0343 (circuit high) and P0344 (intermittent).

Severity: can I keep driving?

Stop and fix promptly

Get this diagnosed promptly. RepairPal rates P0342 'Urgent' and lists an engine that may not start among the symptoms, and OBD-Codes.com lists lack of power, stalling and hard starting. If the engine stalls, loses power or is hard to start, avoid relying on the car in traffic or on the highway until it's checked.

Common symptoms

Check engine light on
Lack of power or decreased engine performance
Stalling (listed by OBD-Codes.com)
Hard starting, or the engine may not start
Increased fuel consumption (listed by RepairPal)

Likely causes

Roughly most to least common, based on the sources below. Your vehicle may differ.

Failed camshaft position sensor
Sensor wiring open or shorted
Poor electrical connections, such as a corroded connector or bent pins
Bad or weak battery (listed by OBD-Codes.com, which says a low battery can set this code)
Faulty starter or poor wiring to the starter (listed by OBD-Codes.com)
Broken tone ring (reluctor wheel), the toothed ring the sensor reads (listed by RepairPal)
Engine computer (PCM) failure, which is less likely (listed by RepairPal)

Diagnostic steps you can do

⚠ Before you start

Work on a cool engine, parked on level ground with the parking brake set. Never work under a car supported only by a jack.

Read and write down all stored codes and freeze frame data. If other camshaft or crankshaft position codes (such as P0340 or P0335) are also stored, mention them, since they change where to look.
Search for technical service bulletins (TSBs) for your vehicle first, as OBD-Codes.com recommends.
Check the battery's condition and charge. OBD-Codes.com says a low battery can set this code.
Check the wiring to the starter for corrosion, loose connections or frayed insulation, and have the starter checked for excessive current draw, which OBD-Codes.com says indicates a weak starter.
Find the bank 1 camshaft position sensor (your repair manual shows its exact location; OBD-Codes.com says cam sensors mount at the front or rear of the camshaft). Inspect its connector for corrosion and bent pins; OBD-Codes.com suggests applying dielectric grease to the pins.
Don't assume the sensor is the answer. RepairPal warns that just replacing a sensor may not fix underlying issues, such as a wiring fault or a broken tone ring.

Typical fixes

Charge or replace a weak battery
Repair starter wiring or replace a weak starter if testing shows excessive draw
Repair open or shorted wiring, or clean and repair a corroded connector
Replace the camshaft position sensor (RepairPal's most common repair for this code, and OBD-Codes.com's final step)
Repair a broken tone ring if inspection finds one
Diagnose and replace the PCM only after the sensor, wiring, battery and starter check out

Repair costs vary widely by vehicle, region, parts brand and shop, so we don't quote prices. Get a written estimate after diagnosis.

🛠 When to call a pro

The engine won't start or stalls
The battery, starter, wiring and sensor check out and the code comes back
Checking the tone ring or starter draw needs tools or disassembly you don't have
Other camshaft or crankshaft position codes are also stored

Where to buy

Plain search links. Always match parts to your exact year, make, model and engine.

OBD2 scanners on Amazon Parts at Advance Auto Parts catalog at RockAuto

FAQs

Can I drive with P0342?

It's not a good idea to put it off. RepairPal rates P0342 'Urgent' and says the engine may not start, and OBD-Codes.com lists stalling and hard starting. The car might run now and not restart later.

Is P0342 always a bad camshaft sensor?

No. Replacing the sensor is RepairPal's most common repair, but both sources list wiring and connection problems. OBD-Codes.com adds a weak battery or starter, and RepairPal adds a broken tone ring and PCM failure. Check the battery, starter wiring and sensor connector before buying parts.

Why would a battery or starter cause P0342?

OBD-Codes.com says a low battery can set this code and lists a faulty starter and poor starter wiring as causes, which suggests low voltage while cranking can leave the sensor signal too weak to read. Test the battery and check the starter for excessive draw.

What's the difference between P0342 and P0347?

Both mean camshaft position sensor A's circuit signal is low. P0342 is bank 1 (the side with cylinder 1) and P0347 is bank 2, per OBD-Codes.com's numbering. RepairPal's title for P0342 doesn't mention the bank, so check your vehicle's service information to confirm which sensor it means.

Sources

Last reviewed 2026-10-24. Code definitions and repair steps can vary by manufacturer. Confirm with your vehicle's service information.