P2AE7: Intake Air O2 Sensor Negative Current Control Circuit Low Bank 1

P2AE7 is set when the virtual-ground return of the bank 1 intake oxygen sensor is pulled below its bias. In operation this lead sits roughly 2.5 V above chassis, as Saab's 2010 9-5 documents for its wide-band probe; a wire touching the engine block, a bracket or the intake pipe drags it towards zero. The pump cell then has hardly any room to work, and both the measured oxygen share and the EGR rate derived from it become meaningless. Ford counts a grounded VM lead among the faults that set P0131 on its exhaust probes. No manufacturer documents P2AE7 itself, so this rests on CARB's range-check duty and the Bosch pin layout. P2AE6 is the open return, P2AE8 the high case, P2AE4 the low fault on the pump lead, P2AF0 bank 2.

Bank 1 is the side of the engine with cylinder 1. Inline engines only have this bank.

Symptoms

• Check engine light on
• EGR cut back, possibly higher NOx

Most likely causes

• Return lead chafed against engine or bracket
• Internal short of the common electrode to ground
• Bias source in the ECM faulty

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the wiring and connector of the sensor indicated
2. With the connector unplugged, check whether the signal wire is making contact with ground.
3. Look for exhaust leaks
4. Check the signal in live data with the engine warm
5. Check the fuse and the heater resistance if the code mentions it
6. Replace the sensor if it has power and does not respond

Good to know

• Repair difficulty: medium
• It affects emissions.

What each character of P2AE7 means

• P: Powertrain: engine and transmission
• 2: Generic code: same on every make
• A: Hybrid or air and fuel
• E7: Specific fault in that system

Frequently asked questions

Can I keep driving with code P2AE7?

Yes, you can normally drive in moderation, but get it repaired soon: you will use more fuel and the catalytic converter can be damaged over time.

What causes code P2AE7?

The most common causes are: return lead chafed against engine or bracket; internal short of the common electrode to ground; bias source in the ECM faulty.

Related codes

• P2AE6Intake Air O2 Sensor Negative Current Control Circuit Open Bank 1
• P2AE8Intake Air O2 Sensor Negative Current Control Circuit High Bank 1
• P2AE4Intake Air O2 Sensor Pumping Current Circuit Low Bank 1
• P2AF0Intake Air O2 Sensor Negative Current Control Circuit Low Bank 2
• P2252O2 Sensor Negative Current Control Circuit Low (Bank 1 Sensor 1)

Sources

• saabwisonline.com: dtc p2237 p2239 p2243 p2251 or p2626
• newtonnet.co.uk: fordobd2012
• bosch-motorsport.com: Data Sheet 69034379 Lambda Sensor LSU 4.9
• law.cornell.edu: 13 CCR 1968.2

Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.