Hey there,

I own a Volvo S60 2001 2.0 T S B5204T5 M56 and I have developed an issue.
A while back my cruise control started working inconsistently, on and off. I then also got an Engine System Service required message which was a P2131 code. I cleared the code, the cruise control worked for a day but then stopped permanently. The code and message never returned. I decided to test my pedal sensors.
Here's what I tried before that:

• Engaging while lifting the pedals
• Engaging with the steering wheel turned at different angles

To no avail.
I have gathered some data from the sensor below and was hoping someone could help me make sense of it or even point me in the direction of a wiring diagram. I am quite new to car electrics.

Accelerator Pedal Connector (6 wires: Blue-green, Blue-white, Grey-red, Brown, Black, Black-white)

Live checks (ignition ON, chassis ground):

• Black-white: 5V
  
• Black: 0V
  
• Blue-green: 11.1V (battery ~11.9V at time)
  
• Blue-white: 0.817V rest → 8.65V pressed
  
• Grey-red: 35 mV rest → ~50 mV pressed (jumps ±20 mV)
  
• Brown: 0.428V rest → 4.3V pressed
  

Wiggling the harness:

• Brown, grey-red, blue-white → stable
  

Resistance checks (pedal prongs, battery disconnected):

• Blue-white ↔ Grey-red: 0 Ω
  
• Blue-white ↔ Blue-green: ~10 MΩ
  
• Grey-red ↔ Blue-green: 0 Ω
  
• Brown ↔ Blue-green: 0 Ω
  

Resistance checks (harness side, battery disconnected):

• Blue-white ↔ Grey-red: 5.3 kΩ
  
• Blue-white ↔ Blue-green: 5.2 kΩ
  
• Grey-red ↔ Blue-green: 11 Ω
  
• Black ↔ Blue-green: 12 Ω
  
• Brown ↔ Blue-green: 2.6 kΩ
  

Brake Pedal Switch (live test)

• Yellow: 11.5V pressed, ~11 mV released
  
• Red: 0V
  

Clutch Pedal Switch (live test)

• Black wire: 3.3V rest → 1V pressed
  
• Brown wire: 1.2–33 mV
  

Observations

• Grey-red shows almost no voltage response (stuck near 0 V).
  
• Blue-white shows abnormally high max voltage (8.6 V).
  
• Pedal prong tests show shorts: signals tied to each other and to 12V.
  
• Harness side also shows low resistance between signal and 12V supply, and ground and supply.
  
• Battery low at ~11.9V.

I appreciate any help at all!!!