A 2008 Mitsubishi Pajero IV rolled in with a hard 90 km/h speed limit and a C1456 code that refused to clear even after a new center diff lock switch. The technician noted the vehicle would not go over 90 km/h, and despite swapping the switch, the fault remained permanent. The vehicle also presented codes P000A and U100A alongside the stubborn C1456.
When a drivetrain code refuses to clear and the vehicle is stuck in a severe speed restriction, it is a common instinct to link the two symptoms together. However, our diagnostic data for these specific codes points to two completely separate hardware failures that happen to overlap.
The overcurrent transfer case fault
The C1456 code is set by the 4WD/Transfer control unit when the measured current through the actuator or coupling coil exceeds 6.0 amps. The fact that it will not clear even with the ignition on points directly to a permanent short to chassis ground in the wiring harness, which we rank as an 85 percent probability.
On the Pajero IV, this harness runs from the cabin down along the gearbox crossmember and over the top of the transfer case. It frequently chafes against metal brackets, crossmembers, or heat shields. A rubbed through wire resting on ground instantly draws maximum current, locking the code permanently. The recommended tests here are a resistance measurement to chassis ground on the wires from the 4WD ECU to the transfer case connector, alongside a visual and mechanical inspection of the harness above the gearbox crossmember.
Why a transfer case code does not cause limp mode
The technician linked the 90 km/h speed restriction to the stubborn C1456 code, but the data shows this is a separate issue entirely. The speed limit is triggered by the engine control unit placing the 4M41 engine into Limp Home Mode due to code P000A, which indicates a slow response in the 'A' camshaft position.
The 3.2-liter 4M41 engine is known for timing chain stretch and wear on the upper chain guide. When the chain stretches or the hydraulic tensioner fails to maintain correct tension, a phase angle error occurs between the crankshaft position (CKP) and camshaft position (CMP) signals. The engine control unit detects this delayed response, sets P000A, and cuts torque and speed to prevent catastrophic valve damage. To verify this, the technician needs to inspect the upper chain guide under the valve cover, measure the tensioner piston protrusion, and read the camshaft to crankshaft synchronization in live data.
Checking the internal transfer case components
If the wiring harness is intact, the C1456 overcurrent could stem from an internal short in the transfer case coupling coil or magnetic actuator. The specification for this coil is an internal resistance between 2.2 and 4.0 ohms.
If the insulation lacquer on the copper windings breaks down from age and heat, an internal short occurs between the windings. This drops the resistance drastically, causing the current to spike above the 6.0 amp limit the moment the control unit activates the circuit. Since the technician only replaced the position switch and not the coil itself, the overcurrent state persists. Diagnosing this requires a resistance measurement directly across the coupling coil terminals and an insulation test between the coil pins and the metal housing of the transfer case.
The role of the oil control valve
For the P000A code, another distinct possibility is a clogged oil control valve (OCV) or contaminated engine oil. The camshaft response relies entirely on proper oil pressure and flow. The 4M41 engine, especially when equipped with a diesel particulate filter, is sensitive to oil dilution from repeated regenerations or carbon deposits in fine oil passages.
If the internal micro filter of the OCV clogs with soot particles, or if the oil is severely degraded, the oil feed to the hydraulic actuator or tensioner is delayed. The engine control unit registers this as a slow camshaft response. The necessary tests are checking the oil level, evaluating viscosity and diesel dilution, and visually inspecting the OCV micro filter after removal.
Splitting the diagnosis
When multiple systems report faults at the same time, it is easy to assume one is causing the other. In this case, treating the drivetrain fault and the engine speed restriction as two separate hardware issues is the only way forward. I am curious how many workshops see this specific combination of codes on the Pajero IV and initially assume the transfer case is locking the vehicle speed.