C1242 Scion Code - IG2 Power Source Circuit
Quick Answer
If there is a problem with the Master Cylinder Solenoid (Skid Control ECU) power supply circuit, the skid control ECU outputs the DTC and prohibits operation under the fail-safe function. Common causes include Faulty Battery, Charging System, Faulty Master Cylinder Solenoid (Skid Control ECU). Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
- What it means
- C1242 Scion indicates IG2 Power Source Circuit.
- Common causes
- Common causes include Faulty Battery, Charging System, Faulty Master Cylinder Solenoid (Skid Control ECU).
- Severity
- High - diagnose this code as soon as possible.
- Can I drive?
- Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Code C1242 Scion Description
If the voltage supplied to terminal IG2 is not within the DTC detection threshold due to malfunctions in parts such as the battery and generator circuit, this DTC is stored.
What are the Possible Causes of the DTC C1242 Scion?
- Faulty Battery
- Charging System
- Faulty Master Cylinder Solenoid (Skid Control ECU)
How to Fix the DTC C1242 Scion?
Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.
What is the Cost to Diagnose the Code?
Labor: 1.0
To diagnose the C1242 Scion code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.
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Frequently Asked Questions about C1242 Scion Code
1. What are the common symptoms of OBDII code C1242 (IG2 Power Source Circuit) in a Scion?
The common symptoms of OBDII code C1242 in a Scion may include issues with starting the vehicle, intermittent electrical failures, and a check engine light illuminating on the dashboard.
2. What are the possible causes of OBDII code C1242 in a Scion?
Possible causes of OBDII code C1242 in a Scion include a faulty ignition switch, damaged wiring or connectors in the ignition circuit, a malfunctioning ignition relay, or a problem with the power supply to the ignition system.
3. How can I diagnose OBDII code C1242 in my Scion?
Diagnosing OBDII code C1242 in your Scion involves using a diagnostic scanner to retrieve the fault code, inspecting the ignition system components for any visible damage, and testing the electrical connections and circuits related to the IG2 power source.
4. Is it safe to continue driving my Scion with OBDII code C1242 present?
It is not recommended to continue driving your Scion with OBDII code C1242 present, as it indicates a potential issue with the IG2 power source circuit that could lead to more serious electrical problems or difficulty starting the vehicle.
5. Can I repair OBDII code C1242 in my Scion on my own?
Repairing OBDII code C1242 in your Scion may require advanced automotive knowledge and tools. While simple fixes like checking and tightening loose connections can be done by DIY enthusiasts, complex issues may need to be addressed by a professional mechanic.
6. Are there any specific repair tips for resolving OBDII code C1242 in a Scion?
When repairing OBDII code C1242 in a Scion, it is important to carefully inspect all components of the IG2 power source circuit, perform thorough electrical testing, and replace any faulty parts with genuine Scion components to ensure proper functionality.
7. How much does it typically cost to repair OBDII code C1242 in a Scion?
The cost of repairing OBDII code C1242 in a Scion can vary depending on the specific cause of the issue, the extent of the damage, and the labor rates in your area. It is recommended to obtain quotes from multiple mechanics for an accurate estimate.
8. Can OBDII code C1242 in a Scion cause other electrical problems in the vehicle?
Yes, OBDII code C1242 in a Scion can potentially cause other electrical problems in the vehicle, as it indicates a fault in the IG2 power source circuit, which is essential for proper operation of various electrical components in the car.
9. How urgent is it to address OBDII code C1242 in a Scion?
It is advisable to address OBDII code C1242 in a Scion as soon as possible to prevent further electrical issues or potential failure to start the vehicle. Ignoring the code could lead to more costly repairs down the line.
10. Can a faulty battery or alternator cause OBDII code C1242 to appear in a Scion?
While a faulty battery or alternator can sometimes lead to electrical issues in a vehicle, OBDII code C1242 specifically relates to problems in the IG2 power source circuit of a Scion, which is separate from the battery and alternator.
Discuss the causes and fixes for C1242 Scion OBDII Code
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Hi, few months ago the maintenance required light along with tire pressure symbol, took it to a shop they checked the tires and adjusted the air but the lights on the dashboard wouldn’t go away after trying to reset it few times. They said the fuse might be blown and can be expensive. Few days later the engine light, also came on. I drove a short distance with the car once or twice and then stopped. After few days when I turned the car on, the check engine light was gone while the maintenance required light was and still is on. The oil and filter was just changed right before all of this happening, and a new battery was also purchased and installed by auto zone.
I appreciate Any suggestions or thoughts. Thank you in advance-
Thanks for the detailed description — that really helps narrow it down.
The C1242 Scion code usually points to a power supply issue to the ABS system, specifically the IG2 (Ignition 2) circuit. This is likely unrelated to the maintenance light or tire pressure directly, but could explain why certain systems are acting oddly.
Here are some suggestions:
1. Maintenance Light Stays On
This light is usually tied to mileage, not necessarily a problem. If you just had the oil changed, the shop should’ve reset it — if not, you can do it yourself (instructions depend on the model, but usually involve the trip reset button and ignition cycling). It doesn’t go off automatically after a service — it needs a manual reset.
2. Tire Pressure Light
If the air pressure is correct and the TPMS light won’t turn off, it could be:
- A faulty TPMS sensor (battery inside goes bad over time)
- A communication issue with the TPMS module
- Or possibly a blown fuse that also powers the TPMS/ABS circuits — which may be what the shop meant.
A blown fuse in the IG2 circuit (which powers things like ABS, TPMS, etc.) could cause multiple warning lights and might have triggered the C1242 code. Replacing that fuse is not usually expensive — unless there's an underlying wiring problem causing it to blow repeatedly.
3. Check Engine Light Came and Went
That’s fairly common with intermittent issues. If the fault was temporary and the car didn’t detect it again after a few drive cycles, the light can turn off by itself. Still, it’s worth scanning for any stored (pending) codes that may still be in the memory.
4. Next Steps
- Have the IG2 fuse and circuit checked — this could explain the C1242 and multiple lights.
- Use a scanner to check for ABS or TPMS codes.
- Clear/reset the maintenance light manually.
- If problems persist, consider a full electrical system check, especially if battery connections were disturbed during installation.
Let me know your Scion model and year if you'd like the reset steps or fuse box diagram.
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Hi, thanks for the quick response. My car is a 2008 Scion Tc with 161,000 miles on it. Only few days after I bought it from a third party, the engine light came on, I had to replace the gas cap with an OEM Toyota part since the old one wasn’t airtight. I must say, I was shocked to see black, charcoal-like, sooty material, when I first opened the gas tank. Please don’t laugh, but for some reason It didn’t raise a flag so I never bothered to look it up and find out what could cause that till right this minute, as I’m typing, It just hit me!
Most probably, the EVAP system was damaged when I bought the car, but I’ve been driving the car for few years now without even knowing anything about it which could explain why the maintenance required light is still on!
I believe this also may be the reason why the check engine light came back on recently, after a long 2 hour drive, it felt like the car was choking as if I was driving a stick shift on gear 2 the whole time. But few days later, it was just gone by itself!
I’ve had other issues intermittently such as sound system malfunction or passenger window not goin up or down but after few hours or even days, it starts working on its own.
Sorry, I tried my best to keep it short but hey, sometimes the story goes on and on and never ends! ;)
Thanks you for taking the time to listen and wanting to help. I really really appreciate that as it’s hard to find a mechanic who is knowledgable and genuinely wants to solve the problem instead of being dishonest and taking advantage of you!
Anyways….-
Thanks for sharing the full story — that gives a much clearer picture. With a 2008 Scion tC at 161k miles, here’s how I’d break it down:
1. Maintenance Required Light
That light on your Scion is just a mileage reminder for oil changes, not an indicator of a system fault. It doesn’t reset on its own. Since the oil was recently changed, you’ll need to manually reset it:
- Turn the ignition key to “ON” (don’t start the car).
- Set the odometer to Trip A.
- Turn the ignition OFF.
- Hold down the trip reset button and turn the key back to “ON.”
- After a few seconds, you’ll see the dashes count down to zero. Release the button and the light should go out.
2. Check Engine Light and EVAP
The charcoal-like debris you saw in the fuel filler neck is from the EVAP charcoal canister breaking down. When that happens, pieces of charcoal can get sucked into the lines or purge valve and cause EVAP-related codes or hard-start/rough-running issues. It won’t usually set the maintenance light, but it can explain why your check engine light has been on and off. If the car felt like it was choking after a long drive, it may have been pulling contaminated vapor through the purge valve.
3. C1242 and Electrical Quirks
The intermittent sound system and window issues plus the C1242 IG2 power source code all point toward a power supply or ground problem. On these cars, a weak ground connection or worn ignition switch circuit can cause random electrical symptoms across different systems. It would be smart to have the main grounds cleaned and re-tightened, and to check the IG2 fuse and wiring for looseness or corrosion.
4. Next Steps
- Reset the maintenance light manually.
- Inspect the EVAP canister — if it’s breaking apart internally, it needs to be replaced before it causes more drivability issues.
- Have the IG2 circuit and ground connections checked thoroughly.
- If the check engine light returns, scan it right away and note the exact codes — that will confirm whether EVAP or another system is the cause.
You’ve been driving it a while, so nothing sounds catastrophic at the moment, but the EVAP canister and electrical grounds are the two big areas I’d address to stop the cycle of lights and odd behavior.
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I can not thank you enough. You’ve been more than helpful and seem very knowledgeable and patient, I appreciate you. I will go ahead and follow your suggestions and will return here to let you know how it all went down. Thanks again.
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You’re very welcome, Neda — I’m glad the info helped and that you feel more confident about the next steps. I’ll be here when you’re ready to update, and I’ll be happy to guide you further once you see how things go. Safe driving, and thanks again for taking the time to share your story.
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