How to Fix Diagnostic Code P1571

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šŸšØ Diagnostic Profile

Vehicle Make: Chrysler

Description: TCS PWM Circuit No Frequency. The controller is not detecting an expected pulse-width modulated signal on the traction control system circuit. This is a signal-integrity fault that may involve a sensor, actuator, wiring, connector, or control module.

šŸšØ Repair Difficulty Tier

Tier: [Intermediate]

Requires scan tool data review, circuit testing with a digital multimeter or oscilloscope, and possible connector or wiring repair.

šŸ› ļø Resolution Steps

Step 1: Preliminary Inspection

  • Verify battery state of charge and charging system output using a digital multimeter; confirm a stable base voltage (typically in the 12.4Vā€“12.6V key-off range and 13.5Vā€“14.7V with the engine running) since low or unstable system voltage can mimic a PWM signal fault by starving the module or actuator of consistent reference power
  • Inspect the TCS/ABS module connector, the hydraulic control unit (HCU) connector, and any related wheel speed sensor or actuator connectors for corrosion, bent/pushed-out pins, or moisture intrusion ā€” pay close attention to the HCU connector near the brake master cylinder and the main harness grommet where it passes through the firewall or frame rail, as these are common chafe/corrosion points on Chrysler platforms
  • Retrieve all stored DTCs and freeze frame data from the ABS/TCS module and any related modules (PCM, BCM) before clearing codes, noting vehicle speed, ambient conditions, and whether the fault was set during a key-cycle or while driving
  • Inspect the full length of the harness between the TCS/ABS module and the affected actuator or sensor for chafing against suspension components, pinched routing near the subframe, or evidence of aftermarket wiring splices/modifications

Step 2: Diagnostic Verification

  • Use a capable scan tool to confirm whether the PWM circuit fault is current/active or historical, and perform a wiggle test while monitoring live data to determine if the fault is intermittent (connector-related) or constant (open/short)
  • Back-probe the suspect PWM signal circuit at the connector (with the circuit intact and powered) using an oscilloscope; confirm the presence of a switching square-wave signal transitioning between a low and high voltage state at the expected duty cycle, rather than a flat-lined or absent trace, which would confirm a true open or no-signal condition versus a module interpretation fault
  • With the connector disconnected and ignition off, perform continuity and resistance checks on the signal wire and the dedicated ground/return wire end-to-end; resistance should read close to zero ohms (typically under 5 ohms) for a healthy circuit, with no continuity to chassis ground or adjacent circuits
  • With the suspect connector disconnected, check for unwanted voltage or ground shorts on the PWM signal circuit using the multimeter referenced to a known good chassis ground, with the ignition both off and in the run position
  • Confirm the TCS/ABS module itself has proper power and ground supply at its main harness connector by checking for battery voltage on the power feed circuit(s) and verifying less than 0.2V drop on the ground circuit(s) relative to the battery negative terminal

Step 3: Resolution & Reset Process

  • Repair or replace the faulty wiring segment, terminal, or connector as confirmed by the circuit testing above, using proper soldered and heat-shrink or OEM-spec crimp connections ā€” avoid butt-splice-only repairs on high-frequency signal circuits
  • Replace the suspect wheel speed sensor, TCS actuator, or ABS/HCU module only after the wiring and connector have been fully verified as good and the component itself has failed a powered or resistance-based bench/in-circuit test
  • Clear all stored DTCs using the scan tool and perform a supervised road test replicating the speed, braking, and steering conditions captured in the original freeze frame data
  • Re-scan all related modules (ABS/TCS, PCM, BCM) to confirm no active or pending codes have returned, and verify normal ABS/TCS/ESC operation through a scan tool functional test or bi-directional actuator command if supported

šŸ“¦ Parts, Labor, and Budget Estimates

Required Components/Software:

  • Wheel speed sensor (if confirmed faulty): approx. $45ā€“$150 per sensor depending on model and wheel location
  • ABS/TCS wiring harness repair kit or pigtail connector: approx. $20ā€“$75
  • ABS/HCU module (only if confirmed faulty through circuit and component testing): approx. $350ā€“$900 for the part, often requiring core exchange
  • Scan tool with current Chrysler-specific software (e.g., a professional-grade diagnostic platform with OEM Chrysler/Stellantis coverage) for accurate live data, bi-directional tests, and post-repair module verification
  • Diagnostic tools: digital multimeter, automotive oscilloscope, and back-probe/wiggle-test probe kit

Average Component Price:

Approximately $45ā€“$150 for a wheel speed sensor, $20ā€“$75 for a harness/connector repair, and $350ā€“$900+ for an ABS/HCU module if replacement is ultimately required; most cases resolve at the wiring/connector level without full module replacement

Estimated Labor Hours:

Diagnostic time (circuit testing, scope verification, and freeze-frame review): 1.0ā€“1.5 hours book time; wiring/connector repair: an additional 0.5ā€“1.0 hour; wheel speed sensor replacement: 0.3ā€“0.8 hour per sensor depending on location; ABS/HCU module replacement and calibration/bleed procedure: 1.5ā€“2.5 hours, plus module programming time if a dealer-level scan tool is required