Fix P2101: Mechanic’s solutions that WORKED

The P2101 – Throttle Actuator “A” Control Motor Circuit Range/Performance code indicates an issue in the Throttle Actuator Control Motor Circuit. This code is triggered when the Powertrain Control Module (PCM) detects an out-of-range performance problem in the throttle actuator, which plays a crucial role in managing the engine’s air intake. Common causes can include a faulty throttle actuator, wiring issues, or even a malfunctioning PCM.

P2101 quick overview

Meaning	P2101 – Throttle Actuator “A” Control Motor Circuit Range/Performance
Is it serious?	Yes, it can be serious as it directly affects the engine’s throttle response and overall performance. This can lead to issues with acceleration and idling.
Possible causes	– Faulty Throttle Actuator – Wiring issues in the throttle actuator circuit – Poor electrical connections – Faulty Throttle Control Motor – Malfunctioning Powertrain Control Module (PCM)
How to diagnose?	Check the Throttle Actuator: Inspect for physical damage or signs of malfunction. Inspect Wiring and Connections: Look for damaged, loose, or corroded wires and connectors in the throttle actuator circuit. Test Throttle Control Motor: Verify its proper functioning. Check Power and Ground Supplies: Ensure the actuator is receiving appropriate power and ground. Scan for Additional Codes: Look for other codes that might indicate related issues. PCM Inspection: Consider the possibility of a faulty PCM if other tests are inconclusive. Perform System Resets or Relearn Procedures: After any repairs, reset the system or perform necessary relearn procedures.

How to fix P2101 – learn from mechanics

I looked into P2101 service cases at iatn.com website where in the private forums the mechanics seek advice from other mechanics. I looked up a bunch of cases to help you decide how to fix your issue and see what would a real mechanic do to solve it.

Case #1: Mazda

Vehicle Information

• 2003 Mazda 6 i, 2.3L

Issue + Repair History

• Check Engine Light (CEL) and A/T light came on
• Towed vehicle
• P2101 code identified
• Checked wiring from Accelerator Pedal Position (APP) to throttle, voltage readings taken
• Performed wiring test from throttle body to PCM, all checks were okay
• Cleared code and attempted test drive
• Encountered U0073 and U0100 codes (loss of communication with TCM and PCM)
• Searched for related service campaigns or recalls
• Suspected throttle body issues due to P2101 code and throttle body motor noise

Other OBD2 Codes + Test Results

• P2101 (TAC motor circuit range/performance)
• U0073 (Control module communication bus off)
• U0100 (Lost communication with ECM/PCM A)
• Voltage reading at PCM term. 3m was 1.1 volts (specs state 0.40 to 0.60)
• Voltage reading at PCM term 3j was between 0.25 and 0.75 volts

Suggestions to Fix Issue

• Check with the dealer for any reflash related to U codes
• Focus on addressing P codes if U codes have been resolved by reflashes
• Consider replacing the throttle body based on P2101 diagnosis

Final Fix

• Contacted dealer and confirmed reflash for U codes
• Cleared U codes and focused on P2101 code
• Replaced the throttle body to resolve the P2101 code issue

Case #2: Honda

Vehicle Information

• 2007 Honda Ridgeline RTS, 3.5L

Issue + Repair History

• Vehicle idles but throttle doesn’t activate
• MIL, VTM-4, VSA warning lights on
• Codes: P2101 (throttle actuator system malfunction) and P2176 (idle not learned)
• Checked fuses, power at throttle, APP output – all okay
• Tried replacing throttle body; P2101 did not reset, but P2176 persisted
• Ran engine for 30 minutes for idle relearn; P2176 did not clear
• PCM reads all sensors okay except for TPS (no voltage for TPS A or B)

Other OBD2 Codes + Test Results

• P2176 – Idle speed not learned
• P2101 – Throttle actuator malfunction

Suggestions to Fix Issue

• Check pins on APP sensor connector
• Inspect for rodent damage on wiring harness
• Consider PCM failure as a potential cause
• Check the sensor on the strut tower connected to the throttle cable

Final Fix

• Identified that the throttle body had shorted, burning the ECM circuit internally
• Replaced throttle body and ECM, resolving the throttle activation issue

Case #3: Mercedes

Vehicle Information

• 2011 Mercedes-Benz ML350 4Matic, 3.5L

Issue + Repair History

• Vehicle initially brought in for secondary air pump issue
• Key left on for several hours, leading to slow crank and rough running
• Codes set: P2101, P0104, P0418, P0446, P0013, P0010
• Checked all fuses and relays, no problems found
• Unable to clear P2101 code, others returned immediately after start
• No throttle acceleration, car in limp mode

Other OBD2 Codes + Test Results

• P2101 – Throttle Valve Actuator
• P0104 – Mass Air Flow Loose Contact Low Frequency
• P0418 – Air Pump Relay Open Circuit
• P0446 – Charcoal Canister Shut Off Valve Open in Wiring
• P0013 – Right Outlet Camshaft Solenoid Open Circuit
• P0010 – Right Inlet Camshaft Solenoid Open Circuit

Suggestions to Fix Issue

• Check for issues with the engine control module
• Investigate if the vehicle was jump-started
• Perform a hard reset of the system
• Check throttle body and throttle actuator
• Consider the possibility of a fried ECM due to prolonged key on

Final Fix

• A hard reset of the system resolved the issue

Case #4: Chevrolet

Vehicle Information

• 2007 Chevrolet Trailblazer LS, 4.2L

Issue + Repair History

• Vehicle running poorly, setting codes related to throttle control
• Codes: P2101 (ETC), P1682 (Ignition circuit)
• No power found on fuse #23 for throttle control
• Relay #57 not getting grounded; manually grounding the relay improved performance
• Evap code present but unclear if related

Other OBD2 Codes + Test Results

• P2101 – Throttle Control System
• P1682 – Ignition Circuit

Suggestions to Fix Issue

• Check the yellow wire, believed to be pin 40, for ground issues
• Possible causes include a bad PCM, ignition switch, or broken wire

Final Fix

• Found a broken yellow wire, along with a few others, about 4-5 inches from the PCM coming out of the blue connector
• The break was located where the wire took a bend and had signs of water corrosion
• Repaired all visibly damaged wires and checked others for potential hidden damage
• Vehicle started and ran well after repairs

Case #5: Nissan

Vehicle Information

• 2006 Nissan 350Z Touring, 3.5L

Issue + Repair History

• Vehicle towed in due to overheating
• In limp mode on startup, setting codes P2100 and P2101
• Observed throttle power PID switching from “on” to “off” during startup
• Primary concern with IPDM (Intelligent Power Distribution Module)

Other OBD2 Codes + Test Results

• P2101 – ETC Function/Circuit
• P2100 – ETC Motor Power
• U1001 – CAN Communication Circuit

Suggestions to Fix Issue

• Check IPDM, located at the rear right corner of the engine compartment, next to the battery
• Consider checking fuse 87, throttle control relay, wiring, and PCM
• Advised to ensure adequate access to service information before proceeding

Final Fix

• Discovered the PCM was not receiving power from the IPDM throttle relay
• Replaced the IPDM
• Vehicle exited limp mode after the replacement

Advice	Description of Diagnostic Step
Check Throttle Actuator and Wiring	Inspect throttle actuator for proper function and wiring for any damage or disconnections.
Examine Power Supply to Throttle Actuator	Verify if the throttle actuator is receiving the correct voltage and power supply.
Inspect PCM and Related Circuitry	Check the Powertrain Control Module (PCM) for faults and review the circuitry for any issues.
Verify Ground Connections	Ensure all ground connections related to the throttle system and PCM are secure and intact.
Consider PCM Replacement	If all other checks are inconclusive, consider the possibility of a faulty PCM needing replacement.
Perform System Resets or Relearn Procedures	After repairs, perform necessary system resets or relearn procedures as specified for the vehicle.
Investigate Related Control Modules	Check other related control modules, like the IPDM in Nissan vehicles, for any malfunctions that might affect the throttle.
Check for Faulty or Damaged Sensors	Examine sensors like the crankshaft or camshaft sensors that might indirectly affect the throttle system.
Test Power and Grounds to Throttle Body	Ensure the throttle body has proper power and ground connections.
Check for Corroded or Damaged Wiring	Inspect the wiring harness for corrosion, breaks, or damage, particularly in areas prone to moisture or wear.