A faulty transmission control module (TCM) most often causes limp mode with the gearbox stuck in one gear, harsh jolts when you select D or R, erratic gear changes, flashing PRND letters and a gearbox or engine warning light. However, the same symptoms are often caused by a low gearbox oil level, a weak battery, a poor earth or a faulty sensor. To test a transmission control module, start by checking the battery and reading the fault codes with a diagnostic tool that can talk to the gearbox control unit, then check the power supply, the connector, the oil and the live data. Below we explain the symptoms, the diagnostic steps and what the most common fault codes mean.
Automated Manual Transmission Control Unit Citroën C2 C3 Siemens S122754002D 9662746780 SIM821
Vendors's code: S122754002D
Product code: ECBD-10596
Barcode:
Code 39:
ISBN:
£495.64
Price
£495.64
£609.64
Price
£609.64
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Automated Manual Transmission Control Unit Citroën C2 C3 Siemens S122754002D 9662746780 SIM821
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Transmission Control Unit S122754002D – does it fit your Citroën C2?
This is a used, working Siemens automated manual transmission control unit with part numbers S122754002D, 9662746780 and SIM821. It fits: Citroën C2, C3 (SensoDrive gearbox). Before buying, compare the numbers with the label on the control unit in your car.
Automated Manual Transmission Control Unit Siemens S122754002D – Citroën C2, C3
An automated manual gearbox (SensoDrive) is a manual gearbox in which the clutch and gear changes are operated by actuators. The control unit (TCU) decides when to disengage the clutch and change gear and controls the actuators – the driver has no clutch pedal. This unit fits: Citroën C2, C3.
Part numbers to compare
- S122754002D – control unit manufacturer number (Siemens), on the label: S122754002 D
- 9662746780 – Citroën part number
- SIM821 – additional marking
The same numbers should appear on the control unit in your car. The car model alone is not enough – control units differ in software version and configuration.
Signs of a faulty transmission control unit
When the transmission control unit starts to fail, the most common signs are:
- inability to engage a gear or pull away,
- a gearbox or clutch fault message,
- jerky gear changes,
- no communication with the control unit in the diagnostic tool.
Before replacing it, check the battery and power supply – automated manual gearboxes are sensitive to low voltage – as well as the earth connections and connectors, and read the fault codes. After replacement, the gearbox usually needs an adaptation (including clutch bite point learning) with a diagnostic tool.
Frequently asked questions
| Which car does the S122754002D control unit fit? |
|---|
| It fits: Citroën C2, C3. Before buying, compare the numbers with the label on the control unit in your car. |
| Which number should I compare? |
| Ideally all of them: S122754002D is the control unit manufacturer number, 9662746780 is the Citroën part number and SIM821 is an additional marking. You will find them all on the control unit label. |
| Does the control unit need programming after replacement? |
| Usually yes – after fitting, the gearbox is adapted (including clutch bite point learning) with a diagnostic tool. |
| What condition is this control unit in? |
| It is a used part in good working condition. The warranty period is shown in the product specification table. |
Not sure whether this control unit fits your car? Send us a photo of your control unit label and we will confirm compatibility.
