What does it mean?
P1652 is a Powertrain (engine, transmission, fuel system) fault code. It indicates: Powertrain Induced Chassis Pitch Output Circuit Malfunction .
Symptoms
- MIL on, often together with a suspension or ride control warning lamp
- Adaptive damping stays in a default setting, so the ride feels unusually harsh or floaty
- Body pitch under acceleration and braking is no longer controlled
- Related codes stored in the chassis or suspension module as well
- Usually no change in engine performance, which makes the fault easy to overlook
Likely causes
- Open, shorted or high-resistance signal wire between the engine module and the suspension/chassis control module
- Corroded, spread or backed-out terminals at either module connector
- Poor shared ground between the two modules
- Harness damage where the wire runs under the carpet, through a sill or past a grommet
- Failed input stage in the suspension control module
- Failed output driver in the engine control module
- A module replaced without the required coding or calibration
How to fix it
- Scan the suspension and chassis modules too, and compare their codes with the engine side
- Unplug and inspect both module connectors for corrosion, moisture and loose terminal tension
- Check the signal wire end to end for continuity and for shorts to ground and battery voltage
- Back-probe the signal with the engine running and watch whether it changes as the throttle is opened
- Voltage-drop test the power and ground at the suspension control module
- Repair the damaged harness section, clear both memories and road test
- Replace and code a module only after the wiring between them is proven good