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2004 Silverado C0226 C0281 C0306 Fault: Transfer Case Issues After Transmission Repair

Model: 04 silverado Fault Code: C0226 Posted: 2015-04-24 19:52

Hello everyone, I recently had my transmission overhauled on my 2004 Chevrolet Silverado. After the work was completed, the mechanic informed me of a 'Service 4WD' message on the instrument panel. Prior to the transmission repair, the 4x4 system functioned perfectly. Immediately after the service, I noticed that the transfer case shift control switch (TCCS) is stuck in 2H mode and will not engage 4H or 4L. Using an OBD-II scan tool, I retrieved three diagnostic trouble codes: C0226 (Front Left Wheel Speed Sensor), C0281 (Brake Lamp Switch), and C0306 (Motor A/B Circuit Malfunction). The mechanic suggested that simply replacing the TCCS would clear these errors. However, I'm concerned about whether this is sufficient. My current understanding is that the ABS systems may resolve C0306 if the sensor circuit is properly restored. Still, I believe a deeper inspection of the transfer case control module (TCCM) is needed — especially since the transmission was removed during the repair. After replacing the front wheel speed sensor and brake light switch, both codes C0226 and C0281 cleared. However, C0306 remains unresolved. I've learned that this code typically requires reprogramming of the TCCM to resolve — a task that must be performed by specialized equipment. Upon further diagnosis with an OBD-II tool after addressing the initial issues, two additional transfer case-related codes appeared: C0379 (Front Axle Circuit Malfunction) and B0790 (Transfer Case Neutral Indicator Circuit). Research indicates these will likely clear once the TCCM is replaced and reprogrammed. I have now arranged to return to the transmission shop, where I’ve been informed that they are responsible for repairing the TCCM as it was removed during their work. I’ll provide an update on the final resolution of all codes.

Related fault codes
C0226C0281C0306
Comments (4)
Anonymous 2015-04-25 14:17

The transfer case issue is likely related to the transmission shop's work — since it functioned properly before removal, the problem probably stems from disassembly or reinstallation. A wheel speed sensor failure is common in this model; using an OBD-II scanner can help verify sensor inputs. For brake light circuit issues, check if brakes lights operate and inspect fuses and switch functionality.

Anonymous 2015-04-25 20:37

I successfully replaced the front wheel speed sensor (cost: $60 at AutoZone) and the brake light circuit switch (cost: $12). Both codes C0226 and C0281 cleared after replacement. However, I believe C0306 cannot be fixed by simple part replacement — it requires reprogramming of the TCCM. I contacted a local garage that can perform this service; they offer significantly lower pricing than dealerships. The TCCM is specifically responsible for transfer case control. After fixing the initial issues, my scanner detected two new codes: C0379 and B0790 — both related to front axle and neutral position in the transfer case. I believe these will resolve once the TCCM is replaced and reprogrammed. I’ll update everyone on the final outcome.

Anonymous 2015-04-26 12:06

As previously noted, this issue should be addressed by the transmission shop — since the transfer case was removed during their work. Is there any indication that they are not responsible for the TCCM repair?

Anonymous 2015-04-26 13:55

I’ve been in contact with the transmission shop since yesterday and have arranged to drop off my vehicle on Monday. The shop owner has agreed that their mechanics should handle the TCCM repair, as it was affected during the transfer case removal. I’ll keep everyone updated on the progress.