Land Rover OBD-II Trouble Codes
-------------------------------------------------The diagnostic trouble codes (DTCs) P2100 through P2103 all relate to issues with the Throttle Actuator Control (TAC) motor circuit. These codes indicate problems with the electronic control of the throttle actuator. Here's a breakdown of each code:
Throttle Actuator Motor Circuit Open,
TAC Motor Range/Performance,
Throttle Control Circuit Low,
Throttle Control Circuit High,
ETC Motor Drive Current Fault,
Diagnostic Overview
The System: These codes focus specifically on the H-Bridge circuit that powers the motor inside the electronic throttle body. The PCM sends a high-current, Pulse Width Modulated (PWM) signal to this motor to precisely position the throttle blade.
P2100 (Circuit Open): There is a complete break in the path to the motor. The PCM sends a signal, but no current flows. This is usually a broken wire or a burnt-out motor.
P2101 (Range/Performance): The motor is drawing current, but the throttle blade isn't moving to the position the PCM is commanding. This often points to stripped gears or an obstruction.
P2102 / P2103 (Low/High): These codes indicate the voltage on the control circuit is either being pulled to ground (short) or is abnormally high, suggesting a short to power or a failing PCM driver.
Common Failure Points
The Throttle Body Motor: The internal brushes of the DC motor can wear out or become "caked" with carbon, leading to an open circuit (P2100) or high resistance.
Terminal Fretting: This is extremely common in "Drive-by-Wire" systems. Vibration causes the metal pins in the connector to wear, creating an intermittent connection that the PCM interprets as a circuit fault.
Internal Gear Failure: If the plastic gears that connect the motor to the throttle blade strip, the motor will spin freely without moving the blade, triggering P2101.
Wiring Harness Rub-Through: The harness leading to the throttle body often vibrates against the engine or intake manifold, wearing through the insulation and causing shorts (P2102/P2103).
Troubleshooting Steps
Resistance Test: Unplug the throttle body and measure the resistance between the two motor pins (usually the two largest pins in the connector). A healthy motor typically reads between 2.0 $\Omega$ and 25.0 $\Omega$. An "OL" or infinite reading means the motor is open.
The "Wiggle" Test: While monitoring the codes on a scan tool, wiggle the wiring harness and connector at the throttle body. If the code toggles from "Active" to "Stored," you have found a bad connection.
Visual Obstruction: Remove the intake hose and check for "coking" (hard carbon deposits) that might be physically jamming the motor's path.
Circuit Load Test: Because this is a high-current circuit, a multimeter can sometimes lie. Professionals often use a test light to ensure the PCM can actually "drive" a load through the wires.
Would you like me to find the specific wiring pinout for your throttle body so you know which pins to test with your multimeter?
P2100 Throttle Actuator Motor Circuit Diagnosis
This video demonstrates how to bypass the PCM and safely "bench test" the throttle body motor to see if it actually moves when 12V is applied.
1. **P2100 - Throttle Actuator Control Motor Circuit/Open:**
- This code suggests an open circuit or lack of continuity in the Throttle Actuator Control motor circuit.
2. **P2101 - Throttle Actuator Control Motor Range/Performance:**
- Indicates a range or performance issue with the Throttle Actuator Control motor circuit.
3. **P2102 - Throttle Actuator Control Motor Circuit Low:**
- Points to a low voltage condition in the Throttle Actuator Control motor circuit.
4. **P2103 - Throttle Actuator Control Motor Circuit High:**
- Indicates a high voltage condition in the Throttle Actuator Control motor circuit.
### Possible Causes:
1. **Faulty Throttle Actuator Control Motor:** Issues with the motor responsible for controlling the throttle.
2. **Wiring Issues:** Problems with the wiring or connectors associated with the Throttle Actuator Control motor circuit.
3. **Throttle Position Sensor Issues:** Malfunctioning throttle position sensor affecting the TAC system.
4. **Faulty Throttle Body:** Problems within the throttle body itself that impact TAC system operation.
5. **Connector Problems:** Faulty connectors or terminal issues in the wiring harness related to the TAC system.
6. **Electronic Control Module (ECM) Issues:** Problems with the ECM responsible for managing the TAC system.
### Diagnostic Steps:
1. **Inspect Throttle Actuator Control Motor:** Check the Throttle Actuator Control motor for signs of damage or wear. If it appears faulty, consider replacement.
2. **Check Wiring and Connectors:** Inspect the wiring and connectors associated with the Throttle Actuator Control motor circuit. Look for any signs of damage, corrosion, or loose connections.
3. **Test Throttle Position Sensor:** Check the throttle position sensor for proper operation. Replace if necessary.
4. **Verify Throttle Body Functionality:** Ensure that the throttle body is mechanically sound and functioning correctly.
5. **Perform Continuity Tests:** Check for continuity in the wiring from the Throttle Actuator Control motor to the ECM.
6. **Check for Short or Open Circuits:** Look for short circuits or open circuits in the Throttle Actuator Control motor circuit.
7. **Verify ECM Operation:** Test the ECM for proper operation. Replace if necessary.
8. **Clear Codes:** After addressing any identified issues, clear the trouble codes and monitor the system for recurrence.
9. **Consider Professional Assistance:** If you are unsure about diagnosing or addressing these issues yourself, or if the faults persist, it's advisable to consult with a qualified mechanic or technician.
Addressing the root cause of the Throttle Actuator Control motor circuit faults is crucial for proper engine performance and throttle response. If in doubt or if the faults persist, seeking professional assistance is recommended for a thorough diagnosis and effective repair.
