all 4 injectors showing fault on diagnosis

[marksmales]

Has anyone ever known all 4 injectors go at once. I have a VW passat 2.0 tdi 2007 plate 140bhp. Had it remapped 2 years ago to 175 bhp. 6 weeks ago the management light came on stating faults on all 4 injectors. Had wiring loom up to injectors changed and a heater plug. 2 days later management light back on. Cleaned egr system and reset computer. same again. Just had all the wiring chased back to ecu and nothing faulty with wiring so reset computer again but not holding my breath and comes back on again. Guy who does my car is a VW /Audi specialist and he thinks it's to do with the mapping. Auto electrician says he can't get his head round it either. I have now had the mapping taken off and computer reset again and management light is back on again. The car runs like a dream so I just don’t understand what the issue is. Any ideas? Im up to aound £300 in bills and still no wiser.