TC-451-24-01 – Engine Compartment Wiring Harness Inspection

🟠 AMBER – Contact Service Partner

Medium severity. Please contact your authorized service partner and arrange a workshop appointment within the next 4 weeks.

Campaign ID: TC-451-24-017
Vehicle: smart fortwo
Model series: 451
Model years: 2007–2014
Campaign type: Technical Service Campaign
Severity: Amber – Medium
Status: Active
Estimated repair time: 0.4–0.8 hours

Campaign Overview

A technical campaign has been introduced for selected smart fortwo vehicles of model series 451.

On affected vehicles, a wiring harness in the engine compartment may not be sufficiently secured by its retaining clip. Over time, vehicle vibration may cause the wiring harness to come into contact with adjacent components.

The wiring harness and its mounting position must therefore be inspected. If signs of contact or damage are found, the affected components must be repaired or replaced according to the procedure below.

Customer Complaint / Possible Symptoms

Customers may report one or more of the following symptoms:

• Engine warning lamp illuminated
• Intermittent engine warning messages
• Irregular engine operation
• Temporary loss of engine power
• Engine may occasionally fail to start
• No customer complaint; condition discovered during routine service

The presence of these symptoms does not automatically confirm that the vehicle is affected by this campaign.

Vehicles Affected

This campaign applies to selected:

smart fortwo Coupé (451)
smart fortwo Cabrio (451)

Production period: 2007–2014

Applicability must always be confirmed using the vehicle identification number (VIN).

Do not perform the campaign based solely on model year or vehicle model.

Cause

The retaining clip used to secure a section of the engine wiring harness may not provide sufficient clearance between the wiring harness and an adjacent engine component.

Continuous movement and vibration can cause the protective covering of the wiring harness to wear over time.

Workshop Procedure

1. Verify Vehicle Eligibility

Check the VIN in the campaign or warranty system.

Proceed only if campaign TC-451-24-017 is shown as open for the vehicle.

2. Prepare the Vehicle

Switch off the ignition and remove the key.

Allow the engine to cool before working in the engine compartment.

Observe all applicable workshop safety instructions.

3. Inspect Wiring Harness

Open the engine compartment access panel.

Locate the engine wiring harness on the right-hand side of the engine assembly.

Inspect:

• Wiring harness routing
• Retaining clip position
• Clearance to surrounding components
• Protective harness covering
• Individual wires and connectors in the affected area

4. Evaluate the Condition

No damage detected

If the wiring harness shows no signs of abrasion or damage:

1. Install the revised retaining clip.
2. Position the wiring harness according to the specified routing.
3. Verify sufficient clearance to adjacent components.
4. Complete the campaign documentation.

Minor abrasion detected

If only the outer protective covering is affected and the individual wire insulation is undamaged:

1. Repair the protective covering using approved wiring-harness repair material.
2. Install the revised retaining clip.
3. Reposition the harness.
4. Verify sufficient clearance.

Wire insulation damaged

If one or more individual wires are damaged:

1. Repair the affected wiring according to the approved electrical repair procedure.
2. Replace the wiring harness if a compliant local repair is not possible.
3. Install the revised retaining clip.
4. Check the affected electrical circuits for correct operation.
5. Clear any related diagnostic trouble codes.
6. Perform a final function test.

Required Parts

Always verify the latest part number in the electronic parts catalog before ordering.

Required Tools

Standard workshop equipment is sufficient.

Depending on the condition found, the following may also be required:

• Diagnostic tester
• Electrical repair kit
• Wiring harness repair tools
• Inspection lamp

No special campaign-specific tool is required.

Diagnostic Check

If warning lamps are illuminated or drivability problems have been reported, perform a vehicle diagnostic scan before beginning the repair.

Record relevant fault codes before clearing the fault memory.

After completing the repair:

1. Clear related diagnostic trouble codes.
2. Cycle the ignition.
3. Start the engine.
4. Check for warning messages.
5. Perform a final diagnostic scan.
6. Confirm that no related faults return.

Completion Criteria

The campaign can be marked as completed when:

• Vehicle eligibility has been confirmed.
• The affected wiring harness has been inspected.
• Any identified damage has been repaired.
• The revised retaining clip has been installed.
• Correct harness routing and clearance have been verified.
• Any required diagnostic checks have been completed.

Warranty / Campaign Claim

Submit the repair under campaign TC-451-24-017 using the applicable campaign operation code.

Record any additional repair work required because of wiring damage separately where permitted by the applicable warranty process.

Important Notes

This campaign is VIN-specific. Not every smart fortwo of model series 451 is affected.

Always check the current campaign status before beginning work.

If the campaign has already been completed and correctly recorded for the VIN, no further action is required.