P0978 on 2014-2015 Land Rover Range Rover Evoque: Causes and Fixes

What's Unique About the 2014-2015 Land Rover RANGE ROVER EVOQUE

The 2014-2015 Range Rover Evoque, equipped with the ZF 9HP48 9-speed automatic transmission, is particularly susceptible to this code due to a well-documented manufacturing defect. Land Rover issued a Technical Service Bulletin (LTB00740NAS2) acknowledging that a faulty crimp on the internal transmission wiring harness is the primary cause, rather than a failure of the solenoid itself. 🎬 See a technician diagnose the P0978 code on this ZF transmission. This makes diagnosing the P0978 code on an Evoque different from many other vehicles where the solenoid might be the first part to suspect.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Symptoms You May Notice

• 'Gearbox Fault' message on the instrument cluster.
• Harsh or delayed gear shifts.
• Transmission may get stuck in one gear (limp mode).
• Check Engine Light or Transmission Warning Light is illuminated.
• Inability to select certain gears.
• Transmission unexpectedly shifts to Neutral.
• Loud noise from the transmission area upon failure.

Most Likely Causes

1. Faulty Crimp on Internal Transmission Wiring Harness 🔴 High Probability This is a known manufacturing issue documented by Land Rover in TSB #LTB00740NAS2. The crimps on the harness can fail, causing an open or high-resistance circuit, leading to a 'Circuit Current Below Threshold' fault.
   How to confirm: A technician will need to access the transmission's internal components to visually inspect the harness and perform electrical continuity and resistance tests on the circuit for Shift Solenoid 'C'. The TSB provides specific diagnostic steps based on the transmission serial number.
   Typical fix: Replace the internal transmission solenoid valve electrical harness.
   Est. part cost: $100-$200
2. Failed Shift Solenoid 'C' ⚪ Low Probability While less common than the harness issue on this specific vehicle, the solenoid itself can fail electrically or mechanically. However, it should only be suspected after the harness is confirmed to be good.
   How to confirm: After confirming the wiring is good, the solenoid can be tested by measuring its internal resistance with a multimeter. A reading outside the manufacturer's specification indicates failure. This should be done after ruling out the more common harness issue.
   Typical fix: Replace the individual shift solenoid or the entire solenoid block/valve body assembly.
   Est. part cost: $50-$150 for a single solenoid
3. Faulty Transmission Control Module (TCM) ⚪ Low Probability
   How to confirm: This is typically diagnosed by exclusion. If the wiring harness and solenoid are confirmed to be good, the TCM is the next suspect. This is a rare cause and should be the last item checked. A dealer-level scan tool is needed for proper diagnosis.
   Typical fix: The TCM may require a software update or complete replacement and reprogramming by a dealer or specialist.
   Est. part cost: $500-$1500

Rare But Worth Checking

• Low or Contaminated Transmission Fluid: While unlikely to directly cause an electrical circuit code, low or dirty fluid can cause erratic shifting and put stress on solenoids, potentially leading to failure. It's a basic check worth performing. Some owners report a 'Gearbox Fault' light was initially addressed by topping up fluid, though the problem later returned, indicating a more severe underlying issue.
• Weak Auxiliary Battery: Many owners have reported that a failing auxiliary battery (used for the stop/start system and to power the TCM) can cause various electronic glitches, including 'Gearbox Fault' messages. This battery is often a small 12V 1.2Ah or 1.4Ah unit located under the glove box. Before performing expensive transmission work, checking the voltage of this battery (should be above 12.5V) is a highly recommended and inexpensive diagnostic step.

Diagnosis Steps

1. Scan the Transmission Control Module (TCM) for all stored fault codes and note any sub-codes (e.g., -19).
2. Check the main and auxiliary battery voltage. A weak auxiliary battery is a known cause of 'Gearbox Fault' messages and should be ruled out early. It is located under the passenger side glove box.
3. Check the transmission fluid level and condition. Ensure it is clean and at the correct level according to the manufacturer's procedure.
4. Inspect the main external transmission wiring harness connector for damage, corrosion, or loose pins.
5. Follow the diagnostic procedure outlined in TSB #LTB00740NAS2. This involves checking the transmission serial number to see if it falls within the affected range.
6. If the vehicle is within the TSB scope, the next step is to gain access to the transmission's internal components by removing the oil pan and valve body.
7. Visually inspect the internal wiring harness for any signs of damage, especially at the crimp points as specified in the TSB.
8. Perform resistance and continuity tests on the circuit for Shift Solenoid 'C' from the connector back to the TCM to isolate the fault to the harness, solenoid, or external wiring.
9. If the harness is faulty, replace it. If the harness tests good, test the resistance of Shift Solenoid 'C' itself.
10. If both the harness and solenoid are good, the issue may lie with the TCM or its external wiring, requiring more advanced diagnostics.

Parts You'll Likely Need

• Transmission Solenoid Valve Electrical Harness (OEM #LR049888) — This is the most common failure point for code P0978 on this vehicle, as identified in Land Rover TSB LTB00740NAS2. A newer part number may be LR086170.
  Trusted brands: Land Rover (Genuine), VEMO
  OEM price range: $100-$200
  Aftermarket price range: $80-$150
• Auxiliary Battery (OEM #PS1212 (PowerSonic)) — A common cause of generic 'Gearbox Fault' messages that can mimic more serious issues. It's an inexpensive part to replace as a primary diagnostic step.
  Trusted brands: PowerSonic
  OEM price range: $20-$40
  Aftermarket price range: $15-$30
• Transmission Fluid, Pan Gasket, Filter — Required for the harness replacement job, as the transmission pan and valve body must be removed.
  Trusted brands: ZF Lifeguard 9, Land Rover Genuine
  OEM price range: $200-$350
  Aftermarket price range: $150-$250

Related Codes That Often Appear With This One

• P0975 — Relates to Shift Solenoid 'B' circuit. Both codes are listed in the same TSB and can be caused by the same faulty internal wiring harness.
• P0981 — Relates to Shift Solenoid 'D' circuit. This is another code mentioned in TSB LTB00740NAS2, pointing to the common harness failure.
• P0984 — Relates to Shift Solenoid 'E' circuit. Also listed in TSB LTB00740NAS2, indicating a high probability of a harness fault affecting multiple solenoid circuits.
• P0710, P0712, P0713 — These codes relate to the transmission fluid temperature sensor circuit and are also included in the same TSB, suggesting they can be triggered by the faulty internal harness.

Technical Service Bulletins (TSBs) & Recalls

• LTB00740NAS2: States that a 'Gearbox Fault' message accompanied by DTCs including P0978-19 may be caused by a faulty crimp on the transmission internal wiring harness. It applies to 2014-2015 Evoque and 2015 Discovery Sport models with the 9HP48 transmission.

Platform-Specific Known Issues

• A 'Gearbox Fault' message may be displayed due to a faulty crimp on the transmission internal wiring harness, as documented in TSB #LTB00740NAS2.
• The rotary gear selector may fail to rise from the center console, which can be caused by a faulty auxiliary battery or a failure in the gear selector module itself.

Mechanic-Grade Diagnostic Values

• Shift Solenoid Coil Resistance — expected: Approximately 25 Ohms at 20°C (68°F).. Failure: A reading significantly higher or lower than the specification, or an open circuit (infinite resistance).
• Solenoid Resistance (Chrysler 948TE equivalent) — expected: 10.0 to 12.0 Ohms for certain solenoids (e.g., Dog Clutch F).. Failure: A reading outside of this range.
• Solenoid Circuit Resistance (from TCM connector) — expected: Below 3.0 Ohms.. Failure: Resistance above 3.0 Ohms indicates an open or high resistance in the wiring between the TCM and the transmission assembly.

Scan Tool Commands That Help

• JLR SDD, iCarsoft LR V4.0, or equivalent professional scanner: Reset Adaptation / Clear Adaptation Values — This is a critical step after replacing the internal harness, solenoids, or transmission fluid. It clears the TCM's learned shift pressure values, forcing it to re-learn, which can resolve jerky or harsh shifting. A specific re-learn drive cycle must be performed afterward.
• JLR SDD or Pathfinder: Configure new module - Transmission Control Module — This dealer-level function is required only if the Transmission Control Module (TCM) itself is replaced. It programs the new module to the vehicle's specific configuration.

Wiring & Ground Locations

• Main Transmission Case Connector — The large, multi-pin electrical connector on the exterior of the transmission casing.. This is the primary diagnostic point for testing the entire internal harness. A technician can perform resistance and continuity checks from the pins at this connector to the pins at the TCM connector to determine if the fault lies in the external wiring, the internal harness, or the solenoid itself without first dropping the transmission pan.

OEM Part Supersession History

• LR049888 → LR086170 — Part revision or update by the manufacturer.
  Heads up: The parts are interchangeable. However, some official Land Rover parts catalogs may confusingly describe LR049888 as 'KIT - TRANSMISSION PRESSURE PIPES', but aftermarket suppliers and the context of TSB LTB00740NAS2 confirm it is the internal wiring harness.

Model Year Variations Within This Range

• 2014-2015: No significant variations related to the P0978 fault are documented within the 2014-2015 model year range specified in the TSB. The faulty internal harness appears to be a consistent issue for this production block.