I have a 2002 ZO6 with 50+ K miles, 3K on new EBCM from Beans, just fired it up after a Borla XR1 exhaust R&R and skip shift eliminator install by a local independent shop. With less than 20 miles since yesterday's shop work, I am throwing TCS code C1241 HC, but without the yellow TCS dash warning light that was symptomatic (along with the ABS warning) of the failure of the original EBCM.

I can use the DIC in manual mode to temporarily extinguish the code, but when I scroll through the DIC systems, the C1241 HC code immediately reappears at TCS. Where should I look for this gremlin? Is it the exhaust installation that may have caused it by disconnecting a ground or sensor, or could it be related to the skip-shift harness ... or something else.

Thanks in advance for both the education and the fix.

 

I hadn't heard of this one before, but I did a search, and did
at least find one relevant posting.

http://forums.corvetteforum.com/show....php?t=1673136

Hope that helps!

 

If I remember correctly, a C1241 has to do with a Wheel Sensor reading. Possibly you disconnected one of the wheel sensors when making your mod and forgot to connect it back?

 

The code doesn't show up under the ABS section of the Service Manual. It is related to the variable effort steering which gets a signal from the EBCM. Not sure the work you had performed would have caused this problem as it was in the rear of the car Vs the front.

DTC C1241

Circuit Description
The variable effort steering (VES) system uses the electronic brake control module (EBCM) to control current to a bi-directional electromagnetic rotary actuator. The EBCM commands current from negative 2 amps to positive 3 amps to the actuator. At low speeds, a negative current is commanded, which assists steering. At medium speeds, no current is commanded and steering is assisted by hydraulics only. At high speeds, a positive current is commanded, which creates steering resistance.

Conditions for running the DTC
• Ignition voltage between 10.5 and 17 volts
• Off state test - Initial ignition ON, no engine rpm or vehicle speed present.
• On state test - If off state test passes, engine rpm and vehicle speed present.

Conditions for Setting the DTC
An open, short to ground, or short to voltage in the VES actuator or the circuits to the actuator.

Action Taken When the DTC Sets
• A DTC C1241 is stored in memory.
• The DIC may display the SERVICE STEERING SYS warning message.
• The VES system is disabled.

Conditions for Clearing the DTC
• A current DTC will clear when malfunction is no longer present.
• A history DTC will clear after 100 consecutive ignition cycles with no malfunction present.
• Using the scan tool.

Diagnostic Aids
The vehicle needs to be driven to view full commanded and feedback current ranges on the scan tool.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
2. Tests if the Commanded and Feedback Current parameters are at the specified value in there active state.
3. Tests if the resistance of the VES actuator is in the specified range.
7. Tests the high effort control circuit for an open or short to voltage.
8. Tests the low effort control circuit for a short to ground.
10. Tests for poor connections at the VES actuator harness connector.
13. Perform the setup procedure after EBCM replacement.
Step Action Value(s) Yes No
Schematic Reference: Steering Controls Schematics
Connector End View Reference: Steering Controls Connector End Views

1 Did you perform the Variable Effort Steering Diagnostic System Check? -- Go to Step 2
Go to Diagnostic System Check - Variable Effort Steering

2
1. Install a scan tool.
2. Start the engine.
3. With the scan tool, observe the Magna Steer Commanded Current and the Magna Steer Feedback Current Data parameters in the Magna Steer data list.
Does the scan tool indicate that the Magna Steer Commanded and Magna Steer Feedback Current parameters are within .05 amps of each other and within specified range? -1.84 to -1.99 A Go to Testing for Intermittent and Poor Connections in Wiring Systems Go to Step 3

3
1. Turn OFF the ignition.
2. Disconnect the VES actuator harness connector.
3. Measure the resistance of the VES actuator.
Does the resistance measure within the specified range? 1.6-3.1 ohms Go to Step 4
Go to Step 10

4 Test the VES actuator and actuator harness for a short to ground. Refer to Testing for Short to Ground and to Wiring Repairs in Wiring Systems.
Was a short to ground located? -- Go to Step 5
Go to Step 6

5 Visually inspect the actuator harness for any cut, chaffed or damaged wires.
Did you find and correct the condition? -- Go to Step 14
Go to Step 12

6 Test the high effort control circuit of the VES actuator for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems.
Did you find and correct the condition? -- Go to Step 14
Go to Step 7

7
Test the high effort control circuit of the VES actuator for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition? -- Go to Step 14
Go to Step 8

8
Test the low effort control circuit of the VES actuator for a short to ground. Refer to Testing for Short to Ground and Wiring Repairs in Wiring Systems.
Did you find and correct the condition? -- Go to Step 14
Go to Step 9

9 Test the low effort control circuit of the VES actuator for an open or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
Did you find and correct the condition? -- Go to Step 14
Go to Step 11

10
Inspect for poor connections at the harness connector of the VES actuator. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition? -- Go to Step 14
Go to Step 12

11 Inspect for poor connections at the harness connector of the EBCM. Refer to Testing for Intermittent and Poor Connections and Connector Repairs in Wiring Systems.
Did you find and correct the condition? -- Go to Step 14
Go to Step 13

12 Replace the VES actuator. Refer to Power Steering Gear Replacement in Power Steering System.
Did you complete the repair? -- Go to Step 14
--
13
Important
Perform the setup procedure for the EBCM. An unprogrammed EBCM will result in the following conditions:
• Inoperative, or poorly functioning DRP/ABS/TCS/VSES/VES/TPM system, if equipped.
• Set DTC C1248
• Set DTC C1255
Replace the EBCM. Refer to Electronic Brake Control Module (EBCM) Replacement in Antilock Brake System.
Did you complete the repair? -- Go to Step 14
--
14
1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.
Does the DTC reset? -- Go to Step 2
System OK



Bill

 

I did some additional Forum research on 1241C before my first post, as well as a Google search, and recognize it is related to Magnasteer malfunction, but the frustration I'm feeling has to do with the cooincidence of the exhaust work and skip-shift harness install and the advent of the code, which was not present in H or C before the work.

A post on another Forum focused on altered pitch resulting from improperly mixing wheel and tires sizes frot to rear, which apparently threw this code, but I'm running OEM wheels and Supercars. However, my new mufflerless XR1 exhaust is about 20 pounds lighter than the Borla touring system I removed (which is for sale, BTW), and the car does now sit about an inch higher at the rear. Opinions?

Concluding, the shop that did my exhaust has committed to tech out the problem electronically using some sophisticated digital gear they use for tuning/reflashing ECMs on both ricer and domestic performance cars, despite the implication that their work was done from the cats back and nowhere near the Magnasteer module. It is possible that the connector from the EBCM to the Magnasteer module on the rack might have gotten loose when they boosted it onto their lift from an auxiliary floor jack, and they did remove the rear wheels while it was on their lift, but I'm unsure of the implication of the sensors at the wheels.

My local Chevy dealer's Vette guru said "HHMMMM, dunno what might be the problem, but bring it in on Tuesday," so that is fallback, but I'm already feeling my wallet beginning to blister again, after having had to replace the EBCM in March.

Thanks for all the input, and I'll be sure to follow up with a post describing the real problem as well as the fix.

 

Thanks to the guys at EB3, an independent speed shop in Northern Virginia, my persistent C1241 code and Magnasteer malfunction is neither current not history, literally. Of course, it had nothing to do with the exhaust R&R or the skip shift eliminator install, but probably was precipitated by the locally high heat and humidity coincidental with my recent shop work.

The culprit, once the EBCM and grounds were eliminated using both the onboard diagnostic tool and a Tech II, was a bent pin and a little corrosion in the harness clip where it connects to the Magnasteer module on the steering rack. Once cleaned, smeared with di-electric grease, and reconnected from under the car, Magnasteer was again functional, and the code went away.

If it had proven to be a malfunction of the Magnasteer module itself, the entire rack had to be replaced because on this model year, the module is integral to the rack. Remanufactured racks go for $350 or more and require a core, plus labor ... and add the cost of the cam you would want to install while the front end was disassembled!

While I had no real problem driving the ZO6 without Magnasteer and rather liked the consistently taught feel of the power steering throughout the speed range, which was not unlike the feel of the manual steering rack on my Miata autocrosser, the persistent code ultimately would have prevented me from passing inspection at the OBDII check interval required to renew my VA tags.

Thanks to all for piling on.

 

The XR1 LOOKS like it should sound great...

Wondering how bad is the drone around 1500 RPM?

And do you have stock cats, and no headers?